Android_06_返回Activity时，传递数据

MainActivity.java

package com.itheima.getresult;

import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;

public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

}

public void click(View c){
//跳转至选择联系人Activity
Intent intent = new Intent(this, ContactActivity.class);
// startActivity(intent);
//用这个api启动的Activity，在销毁时，系统会回调onActivityResult
startActivityForResult(intent, 10);
}

public void click2(View v){
//跳转至选择快捷回复的Activity
Intent intent = new Intent(this, CallbackActivity.class);
//如果希望Activity返回时携带数据，记得以这种方式启动Activity
startActivityForResult(intent, 20);
}
//如果有Activity在销毁时返回了数据，那么就会调用此方法来接收数据
//requestCode:用来区分数据来自于哪一个Activity
//resultCode:用来区分返回的数据是什么类型的
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
// TODO Auto-generated method stub
super.onActivityResult(requestCode, resultCode, data);

String name = data.getStringExtra("name");
if(requestCode == 10){
EditText et = (EditText)findViewById(R.id.et);
et.setText(name);
}
else if(requestCode == 20){
EditText et_content = (EditText)findViewById(R.id.et_content);
et_content.setText(name);
}
}

}

ContactActivity.java
package com.itheima.getresult;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;

public class ContactActivity extends Activity {

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

ListView lv = (ListView) findViewById(R.id.lv);

final String[] objects = new String[]{
"小志",
"逼哥",
"世界级XXX",
"国服第一"
};

lv.setAdapter(new ArrayAdapter<String>(this, R.layout.item_listview, R.id.tv, objects));

//给listview设置条目的点击侦听
lv.setOnItemClickListener(new OnItemClickListener() {

//当某个条目被点击时，此方法调用
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {

//Activity返回时传递数据，也是通过意图对象
Intent data = new Intent();
//把要传递的数据封装至意图对象中
data.putExtra("name", objects[position]);

//当前Activity销毁时，data这个意图就会传递给启动当前Activity的那个Activity
setResult(1, data);

//销毁当前Activity
finish();
}
});
}

@Override
public void onBackPressed() {
// TODO Auto-generated method stub
super.onBackPressed();
}
}

CallbackActivity.java
package com.itheima.getresult;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;

public class CallbackActivity extends Activity {

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

ListView lv = (ListView) findViewById(R.id.lv);

final String[] objects = new String[]{
"免谈，没戏，滚犊子",
"媳妇我错了，求原谅",
"老子才是一家之主"
};
lv.setAdapter(new ArrayAdapter<String>(this, R.layout.item_listview, R.id.tv, objects));

//设置ListView条目的侦听
lv.setOnItemClickListener(new OnItemClickListener() {

@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {

Intent data = new Intent();
data.putExtra("name", objects[position]);
//将数据返回给调用者
setResult(2, data);
//销毁当前Activity
finish();

}
});
}
}

activity_main.xml
<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:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity"
android:orientation="vertical"
>

<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
>
<EditText
android:id="@+id/et"
android:layout_weight="1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:hint="请输入联系人"
/>
<Button
android:layout_weight="0"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="+"
android:onClick="click"
/>
</LinearLayout>
<EditText
android:id="@+id/et_content"
android:layout_weight="1"
android:layout_width="match_parent"
android:layout_height="0dp"
android:hint="请输入短信内容"
android:gravity="top"
/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="快捷回复"
android:onClick="click2"
/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="发送短信"
/>
</LinearLayout>
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >

<ListView
android:id="@+id/lv"
android:layout_width="match_parent"
android:layout_height="match_parent"
></ListView>
</LinearLayout>

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

<TextView
android:id="@+id/tv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="20sp"
/>
</LinearLayout>
总结一下返回数据的操作流程：

第一步：启动Activity

//跳转至选择联系人Activity
Intent intent = new Intent(this, ContactActivity.class);
// startActivity(intent);
//用这个api启动的Activity，在销毁时，系统会回调onActivityResult
startActivityForResult(intent, 10);
第二步：设置activity返回时的数据
//Activity返回时传递数据，也是通过意图对象
Intent data = new Intent();
//把要传递的数据封装至意图对象中
data.putExtra("name", objects[position]);

//当前Activity销毁时，data这个意图就会传递给启动当前Activity的那个Activity
setResult(1, data);

//销毁当前Activity
finish();
第三步：接收数据
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
// TODO Auto-generated method stub
super.onActivityResult(requestCode, resultCode, data);

String name = data.getStringExtra("name");
if(requestCode == 10){
EditText et = (EditText)findViewById(R.id.et);
et.setText(name);
}

}