Android(一)：startActivityForResult方法

先看第一个Activity的布局文件

main.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" > <EditText android:id="@+id/first" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_weight="2" /> <EditText android:id="@+id/second" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_weight="2" /> <Button android:id="@+id/start" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal" android:layout_weight="1" android:textSize="25sp" android:text="start" /> <TextView android:id="@+id/text" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_weight="1" android:paddingLeft="50dip" android:textSize="15sp" android:text="waiting...."/> /> </LinearLayout>  

再看第一个Activity的代码

TestAct.java

package zknu.zhang; 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.EditText; import android.widget.TextView; public class TestAct extends Activity { private EditText firstEditText = null; private EditText secondEditText = null; private Button startBtn = null; private TextView mText = null; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); //根据ID号创建控件对象 firstEditText = (EditText) findViewById(R.id.first); secondEditText = (EditText) findViewById(R.id.second); mText = (TextView)findViewById(R.id.text); //创建Button对象,并绑定监听器 findViewById(R.id.start).setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub doSend(); } /** * 名称：doSend()方法 * 功能：发送消息给另一个Activity * */ private void doSend() { //创建Intent对象,准备传递给其他Activity Intent i = new Intent(TestAct.this,TestAct2.class); //创建Bundle对象,从EditText获得输入并放入键-值对 Bundle mBundle = new Bundle(); mBundle.putString("first", firstEditText.getText().toString().trim()); mBundle.putString("second", secondEditText.getText().toString().trim()); //放入Bundle对象 i.putExtras(mBundle); //调用startActivityForResult()启动另一个Activity //public void startActivityForResult (Intent intent, int requestCode) TestAct.this.startActivityForResult(i, 10); } }); } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { // TODO Auto-generated method stub /*-------------------------------------------------------------- //等效代码 if(requestCode == 10) { if(resultCode == Activity.RESULT_OK) { Bundle mBundle = data.getExtras(); String info = mBundle.getString("RESULT"); updateText(info); //break;//error } } ---------------------------------------------------------------*/ /*-------------------------------------------------------------- switch(resultCode) { case Activity.RESULT_OK: Bundle mBundle = data.getExtras(); String info = mBundle.getString("RESULT"); updateText(info); break; default: break; } ---------------------------------------------------------------*/ switch(requestCode) { case 10: { switch(resultCode) { case Activity.RESULT_OK: { //获取另一个Activity返回来的信息 Bundle mBundle = data.getExtras(); String info = mBundle.getString("RESULT"); //显示信息,更新TextView updateText(info); break; } default: break; } } default: break; } super.onActivityResult(requestCode, resultCode, data); } /** * 名称：updateText(String info)方法 * 功能：将得到的消息显示在TextView * @param info */ private void updateText(String info) { // 获取与操作系统有关的回车换行符 String lineSeparator = System.getProperty("line.separator"); //mText.append(info); this.mText.setText(info + lineSeparator + "ok!"); } }

接着是第二个Activity的xml文件

reply.xml文件

<?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/reply" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal" android:textSize="25sp" android:text="reply" /> </LinearLayout>
第二个Activity的代码

TestAct2.java

package zknu.zhang; 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; public class TestAct2 extends Activity { private Button replyBtn = null; @Override protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); setContentView(R.layout.reply); //创建Button按钮对象,并为其绑定监听器 findViewById(R.id.reply).setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub doReply(); } /** * 名称：doReply()方法 * 功能：将信息返回给第一个Activity * */ private void doReply() { //获得第一个Activity传递的Intent和信息 Intent i = TestAct2.this.getIntent(); Bundle mBundle = i.getExtras(); //通过键,将获得的(值)信息合并 String v1 = mBundle.getString("first"); String v2 = mBundle.getString("second"); String value = v1 + v2; //再创建Intent对象 Intent mIntent = new Intent(); //再创建Bundle对象 Bundle mB = new Bundle(); //放入键-值对 mB.putString("RESULT", value); //放到Intent(相当于extras) mIntent.putExtras(mB); //调用setResult()方法 //public final void setResult (int resultCode, Intent data) TestAct2.this.setResult(Activity.RESULT_OK,mIntent); TestAct2.this.finish(); } }); } }
string.xml文件

<?xml version="1.0" encoding="utf-8"?> <resources> <string name="hello">Hello World, TestAct!</string> <string name="app_name">ActivityForResultApp</string> <string name="other">TestAct2</string> </resources>   

manifest.xml文件

<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="zknu.zhang" android:versionCode="1" android:versionName="1.0"> <application android:icon="@drawable/icon" android:label="@string/app_name"> <activity android:name=".TestAct" android:label="@string/app_name"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <activity android:name=".TestAct2" android:label="@string/other"></activity> </application> <uses-sdk android:minSdkVersion="4" /> </manifest>   

运行效果：