系出名门Android(8) 控件(View)之TextSwitcher, Gallery, ImageSwitcher, GridView, ListView, ExpandableList

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系出名门Android(8) - 控件(View)之TextSwitcher, Gallery, ImageSwitcher, GridView, ListView, ExpandableList

作者：webabcd


介绍
在 Android 中使用各种控件(View)

• TextSwitcher - 文字转换器控件（改变文字时增加一些动画效果）
• Gallery - 缩略图浏览器控件
• ImageSwitcher - 图片转换器控件（改变图片时增加一些动画效果）
• GridView - 网格控件
• ListView - 列表控件
• ExpandableList - 支持展开/收缩功能的列表控件

1、TextSwitcher 的 Demo
textswitcher.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="fill_parent"
    android:layout_height="fill_parent">

    <Button android:id="@+id/btnChange" android:layout_width="wrap_content"
        android:layout_height="wrap_content" android:text="改变文字" />

    <!--
        TextSwitcher - 文字转换器控件（改变文字时增加一些动画效果）
    -->
    <TextSwitcher android:id="@+id/textSwitcher"
        android:layout_width="fill_parent" android:layout_height="wrap_content" />

</LinearLayout>

_TextSwitcher.java

package com.webabcd.view;

import java.util.Random;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.Button;
import android.widget.TextSwitcher;
import android.widget.TextView;
import android.widget.ViewSwitcher;

public class _TextSwitcher extends Activity implements ViewSwitcher.ViewFactory {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        this.setContentView(R.layout.textswithcer);

        setTitle("TextSwithcer");

        final TextSwitcher switcher = (TextSwitcher) findViewById(R.id.textSwitcher);
        // 指定转换器的 ViewSwitcher.ViewFactory
        switcher.setFactory(this);
        
        // 设置淡入和淡出的动画效果
        Animation in = AnimationUtils.loadAnimation(this, android.R.anim.fade_in);
        Animation out = AnimationUtils.loadAnimation(this, android.R.anim.fade_out);
        switcher.setInAnimation(in);
        switcher.setOutAnimation(out);

        // 单击一次按钮改变一次文字
        Button btnChange = (Button) this.findViewById(R.id.btnChange);
        btnChange.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                switcher.setText(String.valueOf(new Random().nextInt()));
            }
        });
    }

    // 重写 ViewSwitcher.ViewFactory 的 makeView()，返回一个 View
    @Override
    public View makeView() {
        TextView textView = new TextView(this);
        textView.setTextSize(36);
        return textView;
    }
}

2、Gallery 的 Demo
gallery.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="fill_parent"
    android:layout_height="fill_parent">

    <!--
        Gallery - 缩略图浏览器控件
            spacing - 缩略图列表中各个缩略图之间的间距
    -->
    <Gallery android:id="@+id/gallery" android:layout_width="fill_parent"
        android:layout_height="wrap_content" android:spacing="20px" />

</LinearLayout>

_Gallery.java

package com.webabcd.view;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageView;
import android.widget.Toast;
import android.widget.Gallery.LayoutParams;

public class _Gallery extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        this.setContentView(R.layout.gallery);

        setTitle("Gallery");

        Gallery gallery = (Gallery) findViewById(R.id.gallery);
        // 为缩略图浏览器指定一个适配器
        gallery.setAdapter(new ImageAdapter(this));
        // 响应 在缩略图列表上选中某个缩略图后的 事件
        gallery.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View v,
                    int position, long id) {
                Toast.makeText(_Gallery.this, String.valueOf(position), Toast.LENGTH_SHORT).show();
            }

            @Override
            public void onNothingSelected(AdapterView<?> arg0) {

            }
        });
    }

    // 继承 BaseAdapter 用以实现自定义的图片适配器
    public class ImageAdapter extends BaseAdapter {

        private Context mContext;

        public ImageAdapter(Context context) {
            mContext = context;
        }

        public int getCount() {
            return mThumbIds.length;
        }

        public Object getItem(int position) {
            return position;
        }

        public long getItemId(int position) {
            return position;
        }

        public View getView(int position, View convertView, ViewGroup parent) {
            ImageView image = new ImageView(mContext);

            image.setImageResource(mThumbIds[position]);
            image.setAdjustViewBounds(true);
            image.setLayoutParams(new Gallery.LayoutParams(
                    LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));

            return image;
        }
    }

    // 需要显示的图片集合
    private Integer[] mThumbIds = { R.drawable.icon01, R.drawable.icon02,
            R.drawable.icon03, R.drawable.icon04, R.drawable.icon05 };
}

3、ImageSwitcher 的 Demo
imageswitcher.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="fill_parent"
    android:layout_height="fill_parent">

    <Gallery android:id="@+id/gallery" android:layout_width="fill_parent"
        android:layout_height="wrap_content" android:spacing="20px" />

    <!--
        ImageSwitcher - 图片转换器控件（改变图片时增加一些动画效果）
    -->
    <ImageSwitcher android:id="@+id/imageSwitcher"
        android:layout_width="fill_parent" android:layout_height="wrap_content" />

</LinearLayout>

_ImageSwitcher.java

package com.webabcd.view;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.AnimationUtils;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.ViewSwitcher;
import android.widget.Gallery.LayoutParams;

// 图片转换器的使用基本同文字转换器
// 以下是一个用 ImageSwitcher + Gallery 实现的经典的图片浏览器的 Demo
public class _ImageSwitcher extends Activity implements
        ViewSwitcher.ViewFactory {

    private ImageSwitcher mSwitcher;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        this.setContentView(R.layout.imageswithcer);

        setTitle("ImageSwithcer");

        mSwitcher = (ImageSwitcher) findViewById(R.id.imageSwitcher);
        mSwitcher.setFactory(this);
        mSwitcher.setInAnimation(AnimationUtils.loadAnimation(this,
                android.R.anim.fade_in));
        mSwitcher.setOutAnimation(AnimationUtils.loadAnimation(this,
                android.R.anim.fade_out));

        Gallery gallery = (Gallery) findViewById(R.id.gallery);
        gallery.setAdapter(new ImageAdapter(this));
        gallery.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View v,
                    int position, long id) {
                mSwitcher.setImageResource(mImageIds[position]);
            }

            @Override
            public void onNothingSelected(AdapterView<?> arg0) {

            }
        });
    }

    public class ImageAdapter extends BaseAdapter {

        private Context mContext;

        public ImageAdapter(Context context) {
            mContext = context;
        }

        public int getCount() {
            return mThumbIds.length;
        }

        public Object getItem(int position) {
            return position;
        }

        public long getItemId(int position) {
            return position;
        }

        public View getView(int position, View convertView, ViewGroup parent) {
            ImageView image = new ImageView(mContext);

            image.setImageResource(mThumbIds[position]);
            image.setAdjustViewBounds(true);
            image.setLayoutParams(new Gallery.LayoutParams(
                    LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));

            return image;
        }
    }

    private Integer[] mThumbIds = { R.drawable.icon01, R.drawable.icon02,
            R.drawable.icon03, R.drawable.icon04, R.drawable.icon05 };

    private Integer[] mImageIds = { R.drawable.icon01, R.drawable.icon02,
            R.drawable.icon03, R.drawable.icon04, R.drawable.icon05 };

    @Override
    public View makeView() {
        ImageView image = new ImageView(this);
        image.setMinimumHeight(200);
        image.setMinimumWidth(200);
        image.setScaleType(ImageView.ScaleType.FIT_CENTER);
        image.setLayoutParams(new ImageSwitcher.LayoutParams(
                LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));
        return image;
    }
}

4、GridView 的 Demo
gridview.xml

<?xml version="1.0" encoding="utf-8"?>

<!--
    GridView - 网格控件
        numColumns="auto_fit" - 列数自适应
        stretchMode - 缩放模式（stretchMode="columnWidth" - 缩放与列宽大小同步）
-->
<GridView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/gridView" android:layout_width="fill_parent"
    android:layout_height="fill_parent" android:padding="10px"
    android:verticalSpacing="10px" android:horizontalSpacing="10px"
    android:numColumns="auto_fit" android:columnWidth="60px"
    android:stretchMode="columnWidth" android:gravity="center">
</GridView>

_GridView.java

package com.webabcd.view;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;

public class _GridView extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        this.setContentView(R.layout.gridview);

        setTitle("GridView");

        GridView gridView = (GridView) findViewById(R.id.gridView);
        // 指定网格控件的适配器为自定义的图片适配器
        gridView.setAdapter(new ImageAdapter(this));
    }

    // 自定义的图片适配器
    public class ImageAdapter extends BaseAdapter {

        private Context mContext;

        public ImageAdapter(Context context) {
            mContext = context;
        }

        public int getCount() {
            return mThumbIds.length;
        }

        public Object getItem(int position) {
            return position;
        }

        public long getItemId(int position) {
            return position;
        }

        public View getView(int position, View convertView, ViewGroup parent) {
            ImageView imageView;
            if (convertView == null) {
                imageView = new ImageView(mContext);
                imageView.setLayoutParams(new GridView.LayoutParams(48, 48));
                imageView.setAdjustViewBounds(false);
                imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
                imageView.setPadding(5, 5, 5, 5);
            } else {
                imageView = (ImageView) convertView;
            }

            imageView.setImageResource(mThumbIds[position]);

            return imageView;
        }

        // 网格控件所需图片数据的数据源
        private Integer[] mThumbIds = { R.drawable.icon01, R.drawable.icon02,
                R.drawable.icon03, R.drawable.icon04, R.drawable.icon05 };
    }
}

5、ListView 的 Demo
main_list_adapter.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
    自定义列表适配器的 layout
-->
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal" android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    
    <TextView android:id="@+id/text" android:layout_width="wrap_content"
        android:layout_height="wrap_content" android:textSize="16sp">
    </TextView>
    
</LinearLayout>

MainListAdapter.java

package com.webabcd.view;

import java.util.List;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;

// 继承 BaseAdapter 以实现自定义的列表适配器
public class MainListAdapter extends BaseAdapter {

    private LayoutInflater mInflater;
    private List<String> mData;

    public MainListAdapter(Context context, List<String> data) {
        mInflater = LayoutInflater.from(context);
        mData = data;
    }

    @Override
    public int getCount() {
        return mData.size();
    }

    @Override
    public Object getItem(int position) {
        return mData.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        TextView text;

        if (convertView == null) {
            // 指定一个 layout 作为自定义列表适配器的 layout
            convertView = mInflater.inflate(R.layout.main_list_adapter, null);
            text = (TextView) convertView.findViewById(R.id.text);
            convertView.setTag(text);
        } else {
            text = (TextView) convertView.getTag();
        }
        
        String mItem = mData.get(position);
        text.setText(mItem);
        
        return convertView;
    }
}

Main.java

package com.webabcd.view;

import java.util.ArrayList;
import java.util.List;

import android.app.ListActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.ListView;

// 此处要继承 ListActivity ，用以实现 ListView 的功能
public class Main extends ListActivity {
    
    private List<String> mData;
    
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setTheme(android.R.style.Theme_Light);
        setContentView(R.layout.main);        
        mData = getData();
        
        // 使用自定义的列表适配器来展现数据
        MainListAdapter adapter = new MainListAdapter(this, mData);
        
        // 如需使用系统内置的列表适配器，则可以使用类似如下的方法
        // ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_expandable_list_item_1, mData);
        
        this.setListAdapter(adapter);
    }

    // ListView 的数据源
    private List<String> getData()    {
        List<String> items = new ArrayList<String>();
        
        items.add("TextView");
        items.add("Button");
        items.add("ImageButton");
        items.add("ImageView");
        items.add("CheckBox");
        items.add("RadioButton");
        items.add("AnalogClock");
        items.add("DigitalClock");
        items.add("DatePicker");
        items.add("TimePicker");
        items.add("ToggleButton");
        items.add("EditText");
        items.add("ProgressBar");
        items.add("SeekBar");
        items.add("AutoCompleteTextView");
        items.add("MultiAutoCompleteTextView");
        items.add("ZoomControls");
        items.add("Include");
        items.add("VideoView");
        items.add("WebView");
        items.add("RatingBar");
        items.add("Tab");
        items.add("Spinner");
        items.add("Chronometer");
        items.add("ScrollView");
        items.add("TextSwitcher");
        items.add("ListView");
        items.add("Gallery");
        items.add("ImageSwitcher");
        items.add("GridView");
        items.add("ExpandableList");
         
        return items;
    }

    // ListView 中某项被选中后的逻辑
    @Override
    protected void onListItemClick(ListView l, View v, int position, long id) {
        Intent intent = new Intent();
        intent.setClassName(this, "com.webabcd.view._" + mData.get(position));

        startActivityForResult(intent, 0);
    }
}

6、ExpandableList 的 Demo
_ExpandableList.java

package com.webabcd.view;

import android.app.ExpandableListActivity;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.Gravity;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.view.ContextMenu.ContextMenuInfo;
import android.widget.AbsListView;
import android.widget.BaseExpandableListAdapter;
import android.widget.ExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.ExpandableListView.ExpandableListContextMenuInfo;

// ExpandableList - 可展开/收缩列表
// 继承 ExpandableListActivity 以实现列表的可展开/收缩的功能
public class _ExpandableList extends ExpandableListActivity {
    
    private ExpandableListAdapter mAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);

        setTitle("ExpandableList");
        
        mAdapter = new MyExpandableListAdapter();
        setListAdapter(mAdapter);
        registerForContextMenu(this.getExpandableListView());
    }

    // 为列表的每一项创建上下文菜单（即长按后呼出的菜单） 
    @Override
    public void onCreateContextMenu(ContextMenu menu, View v,
            ContextMenuInfo menuInfo) {
        menu.setHeaderTitle("ContextMenu");
        menu.add(0, 0, 0, "ContextMenu");
    }

    // 单击上下文菜单后的逻辑
    @Override
    public boolean onContextItemSelected(MenuItem item) {
        ExpandableListContextMenuInfo info = (ExpandableListContextMenuInfo) item.getMenuInfo();
        String title = ((TextView) info.targetView).getText().toString();

        int type = ExpandableListView.getPackedPositionType(info.packedPosition);
        if (type == ExpandableListView.PACKED_POSITION_TYPE_CHILD) {
            int groupPos = ExpandableListView.getPackedPositionGroup(info.packedPosition);
            int childPos = ExpandableListView.getPackedPositionChild(info.packedPosition);
            
            Toast.makeText(this, title + " - Group Index: " + groupPos + " Child Index: " + childPos, Toast.LENGTH_SHORT).show();
            
            return true;
        } else if (type == ExpandableListView.PACKED_POSITION_TYPE_GROUP) {
            int groupPos = ExpandableListView.getPackedPositionGroup(info.packedPosition);
            Toast.makeText(this, title + " - Group Index: " + groupPos, Toast.LENGTH_SHORT).show();
            
            return true;
        }

        return false;
    }

    public class MyExpandableListAdapter extends BaseExpandableListAdapter {

        // 父列表数据
        private String[] groups = 
        { 
            "group1", 
            "group2", 
            "group3",
            "group4" 
        };
        // 子列表数据
        private String[][] children = 
        {
            { "child1" },
            { "child1", "child2" },
            { "child1", "child2", "child3" },
            { "child1", "child2", "child3", "child4" }
        };
        
        @Override
        public Object getChild(int groupPosition, int childPosition) {
            return children[groupPosition][childPosition];
        }

        @Override
        public long getChildId(int groupPosition, int childPosition) {
            return childPosition;
        }

        @Override
        public int getChildrenCount(int groupPosition) {
            return children[groupPosition].length;
        }

        // 取子列表中的某一项的 View
        @Override
        public View getChildView(int groupPosition, int childPosition,
                boolean isLastChild, View convertView, ViewGroup parent) {
            TextView textView = getGenericView();
            textView.setText(getChild(groupPosition, childPosition).toString());
            return textView;
        }

        @Override
        public Object getGroup(int groupPosition) {
            return groups[groupPosition];
        }

        @Override
        public int getGroupCount() {
            return groups.length;
        }

        @Override
        public long getGroupId(int groupPosition) {
            return groupPosition;
        }

        // 取父列表中的某一项的 View
        @Override
        public View getGroupView(int groupPosition, boolean isExpanded,
                View convertView, ViewGroup parent) {
            TextView textView = getGenericView();
            textView.setText(getGroup(groupPosition).toString());
            return textView;
        }

        @Override
        public boolean hasStableIds() {
            return true;
        }

        @Override
        public boolean isChildSelectable(int groupPosition, int childPosition) {
            return true;
        }
                
        // 获取某一项的 View 的逻辑
        private TextView getGenericView() {
            AbsListView.LayoutParams lp = new AbsListView.LayoutParams(
                    ViewGroup.LayoutParams.FILL_PARENT, 48);
            TextView textView = new TextView(_ExpandableList.this);
            textView.setLayoutParams(lp);
            textView.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT);
            textView.setPadding(32, 0, 0, 0);
            return textView;
        }
    }
}

OK
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