Android_Intent_startActivityForResult

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
   android:orientation="vertical"
      tools:context=".MainActivity" >

    <TextView 
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="请输入搜索内容:"
        android:textSize="20sp"
        />
    <EditText 
        android:id="@+id/text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:ems="10"
        android:textSize="20sp"/>
    <Button 
        android:id="@+id/btn_search"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="开始搜索"/>
    <ImageView 
        android:id="@+id/iamge"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:src="@drawable/ic_launcher"
        />
    

</LinearLayout>

MainActivity.java

package com.example.day05_startactivityforresult;

import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.text.TextUtils;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
/**
 * 需求:通过输入搜索的内容查找该内容对应的图片,并显示在页面上
 * 分析:
 * 1.初始控件 初始数据
 * 2.点击搜素
 *     2.1获取搜索内容
 *     2.2存到intent中
 *     2.3开启新的Activity,并传值
 * 3.新的activity
 *     3.1获取传入的值
 *     3.2展示
 *     3.3点击确定按钮
 *         3.3.1将图片地址存起来
 *         3.3.2将值返回给MainActivity
 *         3.3.3关闭当前activity
 *     4.MainActivity获取返回值
 *         4.1判断值是否符合要求
 *         4.2取出值
 *         4.3更新图片
 * @author my
 *
 */
public class MainActivity extends Activity implements OnClickListener{

    private EditText et_input;
    private ImageView image;
    private Button btn_search;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
        btn_search.setOnClickListener(this);
    }
    /**
     * 初始化控件
     */
    private void initView() {
        et_input = (EditText) findViewById(R.id.text);
        image = (ImageView) findViewById(R.id.iamge);
        btn_search = (Button) findViewById(R.id.btn_search);
    }
    /**
     * 按钮单击事件:
     * 点击搜索按钮,跳转页面
     */
    @Override
    public void onClick(View v) {
        //获取搜索内容
        String name = et_input.getText().toString().trim();
        /**
         * 判断输入搜索的内容是否为空
         */
        if(TextUtils.isEmpty(name)){
            return;
        }
        //创建一个Intent对象,并指定要跳转的Activity
        Intent intent = new Intent(MainActivity.this,Activity2.class);
        //将数据存到intent
        intent.putExtra("NAME", name);
        //跳转到新的activity,并设置请求吗
        startActivityForResult(intent, 100);
    }
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if(requestCode == 100 && resultCode == 101){
            int id = data.getIntExtra("IMAGE", -1);
            image.setImageResource(id);
        }
    }

}

Activity2.java

package com.example.day05_startactivityforresult;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class Activity2 extends Activity{
    private TextView tv;
    private Button btn_return;
    private String name;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.layout2);
        //初始化控件
        tv = (TextView) findViewById(R.id.tv_show);
        btn_return = (Button) findViewById(R.id.btn_return);
        //获取传递过来的intent
        Intent intent = getIntent();
        name = intent.getStringExtra("NAME");
        tv.setText(name);
        btn_return.setOnClickListener(new OnClickListener() {
            
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(Activity2.this,MainActivity.class);
                int id = getData();
                //将图片的id设置到intent中
                intent.putExtra("IMAGE", id);
                //跳转到之前的activity并带结果码
                setResult(101,intent);
                //关闭当前活动(很重要!)
                finish();
            }
            });
    }

    private int getData() {
        int returnImgId =R.drawable.ic_launcher; 
        if("deer".equals(name)){
            returnImgId = R.drawable.deer;
        }else if("panda".equals(name)){
            returnImgId = R.drawable.panda;
        }else if("sheep".equals(name)){
            returnImgId = R.drawable.sheep;
        }
        return returnImgId;
    }
}