• 吴裕雄--天生自然ANDROID开发学习:4.1.2 Activity初窥门径


    package example.jay.com.activitytest1;
    
    import android.content.Intent;
    import android.support.v7.app.ActionBarActivity;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.Button;
    import android.widget.EditText;
    import android.widget.RadioButton;
    import android.widget.RadioGroup;
    
    
    public class MyActivity extends ActionBarActivity {
    
        private Button btnregister;
        private EditText editname;
        private RadioGroup rad;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_my);
    
            btnregister = (Button)findViewById(R.id.btnregister);
            editname = (EditText)findViewById(R.id.editname);
            rad = (RadioGroup)findViewById(R.id.radioGroup);
            btnregister.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    String name,sex = "";
                    Intent it = new Intent(MyActivity.this,MyActivity2.class);
    
                    name = editname.getText().toString();
    
                    //遍历RadioGroup找出被选中的单选按钮
                    for(int i = 0;i < rad.getChildCount();i++)
                    {
                        RadioButton rd = (RadioButton)rad.getChildAt(i);
                        if(rd.isChecked())
                        {
                            sex = rd.getText().toString();
                            break;
                        }
                    }
    
                    //新建Bundle对象,并把数据写入
                    Bundle bd = new Bundle();
                    bd.putCharSequence("user",name);
                    bd.putCharSequence("sex",sex);
    
                    //将数据包Bundle绑定到Intent上
                    it.putExtras(bd);
                    startActivity(it);
                    //关闭第一个Activity
                    finish();
    
                }
            });
        }
    }
    
    package example.jay.com.activitytest1;
    
    import android.content.Intent;
    import android.support.v7.app.ActionBarActivity;
    import android.os.Bundle;
    import android.widget.TextView;
    
    
    public class MyActivity2 extends ActionBarActivity {
    
        private TextView txtshow;
        private String name;
        private String sex;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_my_activity2);
    
            txtshow = (TextView)findViewById(R.id.txtshow);
            //获得Intent对象,并且用Bundle出去里面的数据
            Intent it = getIntent();
            Bundle bd = it.getExtras();
    
            //按键值的方式取出Bundle中的数据
            name = bd.getCharSequence("user").toString();
            sex = bd.getCharSequence("sex").toString();
            txtshow.setText("尊敬的"+name + " " + sex + "士"+"恭喜你,注册成功~");
        }
    
    }
    
    2.多个Activity间的交互(后一个传回给前一个)
    

    3.知晓当前是哪个Activity
    

    4.随时关闭所有Activity
    

    具体代码如下:
    
    public class ActivityCollector {  
        public static LinkedList<Activity> activities = new LinkedList<Activity>();  
        public static void addActivity(Activity activity)  
        {  
            activities.add(activity);  
        }  
        public static void removeActivity(Activity activity)  
        {  
            activities.remove(activity);  
        }  
        public static void finishAll()  
        {  
            for(Activity activity:activities)  
            {  
                if(!activity.isFinishing())  
                {  
                    activity.finish();  
                }  
            }  
        }  
    }  
    
    5.完全退出App的方法
    上面说的是关闭所有Activity的,但是有些时候我们可能想杀死整个App,连后台任务都杀死 杀得一干二净的话,可以使用搭配着下述代码使用:
    
    实现代码:
    
    /** 
     * 退出应用程序 
     */  
    public void AppExit(Context context) {  
        try {  
            ActivityCollector.finishAll();  
            ActivityManager activityMgr = (ActivityManager) context  
                    .getSystemService(Context.ACTIVITY_SERVICE);  
            activityMgr.killBackgroundProcesses(context.getPackageName());  
            System.exit(0);  
        } catch (Exception ignored) {}  
    }  
    
    6.双击退出程序的两种方法:
    1)定义一个变量,来标识是否退出
    // 定义一个变量,来标识是否退出
    private static boolean isExit = false;
    Handler mHandler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            isExit = false;
        }
    };
    
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            if (!isExit) {
                isExit = true;
                Toast.makeText(getApplicationContext(), "再按一次退出程序",
                        Toast.LENGTH_SHORT).show();
                // 利用handler延迟发送更改状态信息
                mHandler.sendEmptyMessageDelayed(0, 2000);
            } else {
                exit(this);
            }
            return false;
        }
    return super.onKeyDown(keyCode, event);}
    2)保存点击时间:
    //保存点击的时间
    private long exitTime = 0;
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            if ((System.currentTimeMillis() - exitTime) > 2000) {
                Toast.makeText(getApplicationContext(), "再按一次退出程序",
                        Toast.LENGTH_SHORT).show();
                exitTime = System.currentTimeMillis();
            } else {
                            exit();
                          }
            return false;
        }
            return super.onKeyDown(keyCode, event);
    }
    

    2)方法二:
    通过style进行配置,这个是全局的哦,就是所有的Activity都会加载这个动画!
    
    实现代码如下:
    
    ①在style.xml中自定义style:
    
    <!-- 默认Activity跳转动画 -->
    <style name="default_animation" mce_bogus="1" parent="@android:style/Animation.Activity">
        <item name="android:activityOpenEnterAnimation">@anim/default_anim_in</item>
        <item name="android:activityOpenExitAnimation">@anim/anim_stay</item>
        <item name="android:activityCloseEnterAnimation">@anim/anim_stay</item>
        <item name="android:activityCloseExitAnimation">@anim/default_anim_out</item>
    </style>
    解释:
    
    4个item分别代表:
    
    Activity A跳转到Activity B时Activity B进入动画;
    Activity A跳转到Activity B时Activity A退出动画;
    Activity B返回Activity A时Activity A的进入动画
    Activity B返回Activity A时ActivityB的退出动画
    ②然后修改下AppTheme:
    
    <style name="AppTheme" mce_bogus="1" parent="@android:style/Theme.Light">
            <item name="android:windowAnimationStyle">@style/default_animation</item>
            <item name="android:windowNoTitle">true</item>
    </style>
    ③最后在appliction设置下:
    
    <application
       android:icon="@drawable/logo"
       android:label="@string/app_name"
       android:theme="@style/AppTheme" >
    
    10.设置Activity全屏的方法:
    1)代码隐藏ActionBar
    在Activity的onCreate方法中调用getActionBar.hide();即可
    
    2)通过requestWindowFeature设置
    requestWindowFeature(Window.FEATURE_NO_TITLE); 该代码需要在setContentView ()之前调用,不然会报错
    
    3)通过AndroidManifest.xml的theme
    在需要全屏的Activity的标签内设置 theme = @android:style/Theme.NoTitleBar.FullScreen
    
    11.onWindowFocusChanged方法妙用:
    我们先来看下官方对这个方法的介绍:
    

    12.定义对话框风格的Activity
    直接设置下Activity的theme:
    
    android:theme="@android:style/Theme.Dialog"这样就可以了,当然你可以再设置下标题,小图标!
    //设置左上角小图标
    requestWindowFeature(Window.FEATURE_LEFT_ICON);
    setContentView(R.layout.main);
    getWindow().setFeatureDrawableResource(Window.FEATURE_LEFT_ICON, android.R.drawable.ic_lion_icon);
    //设置文字:
    setTitle(R.string.actdialog_title);  //XML代码中设置:android:label="@string/activity_dialog"
    

      

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  • 原文地址:https://www.cnblogs.com/tszr/p/13583115.html
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