Android之Intent

一. 初步认识

src

Activity_01

package cn.android.lyj;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.view.View;import android.widget.Button;import android.widget.EditText;import android.widget.TextView;public class Activity_01 extends Activity {private static final int SHOW_EDITOR = 0;private EditText editText;@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);editText = (EditText) findViewById(R.id.EditText01);Button button = (Button) findViewById(R.id.Button01);button.setOnClickListener(new View.OnClickListener() {public void onClick(View v) {CharSequence text = editText.getText();Intent intent = new Intent(Activity_01.this, Activity_02.class);intent.putExtra("TEXT", text); // /将传送的数据放置在共同存储区，变量:TEXTstartActivityForResult(intent, SHOW_EDITOR); // 切换到Activity，同时等待回应，设定requestCode=SHOW_EDITOR}});}// Main等待回应信息@Overrideprotected void onActivityResult(int requestCode, int resultCode, Intent data) {if (requestCode == SHOW_EDITOR) {if (resultCode == RESULT_OK) {TextView textView = (TextView) findViewById(R.id.TextView02);textView.setText("RESULT_OK: "+ data.getCharSequenceExtra("TEXT"));}}}}

Activity_02

package cn.android.lyj;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.view.View;import android.widget.Button;import android.widget.EditText;public class Activity_02 extends Activity {@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.sub);Button button = (Button) findViewById(R.id.Button01);final EditText editText = (EditText) findViewById(R.id.EditText01);// 取出变量，变量名称:TEXTBundle extras = getIntent().getExtras();if (extras != null) {editText.setText(extras.getCharSequence("TEXT"));}// 设定Button01按钮的操作button.setOnClickListener(new View.OnClickListener() {public void onClick(View v) {CharSequence text = editText.getText();Intent intent = new Intent(); // 将回传的数据放置在共同存储区，变量名称:TEXTintent.putExtra("TEXT", text);setResult(RESULT_OK, intent); // 回应信息，回到Activity_01的onActivityResult(),并告知处理响应结果resul<span style="white-space: pre;"></span> // tCode是RESULT_OKfinish(); // 结束Activity}});}}
main.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" > <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:id="@+id/TextView01" android:text="Activity_01传送下列信息给Activity_02"/> <EditText android:id="@+id/EditText01" android:layout_width="wrap_content" android:layout_height="wrap_content" /> <TextView android:id="@+id/TextView02" android:layout_height="wrap_content" android:text="等Activity_02回应，显示来自Activity_02信息" android:layout_width="fill_parent"/> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/Button01" android:text="Go!" /></LinearLayout>

sub.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" > <TextView android:id="@+id/TextView01" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Activity_02收到下列信息并回答RESULT_OK" /> <EditText android:id="@+id/EditText01" android:layout_width="wrap_content" android:layout_height="wrap_content" /> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/Button01" android:text="RESULT_OK"/></LinearLayout>

Androidmanifest.xml

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android" package="cn.android.lyj" android:versionCode="1" android:versionName="1.0" > <uses-sdk android:minSdkVersion="10" /> <application android:icon="@drawable/ic_launcher" android:label="@string/app_name" > <activity android:label="@string/app_name" android:name=".Activity_01" > <intent-filter > <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <activity android:label="@string/app_name" android:name=".Activity_02" /> </application></manifest>

二. 运行结果

启动后

输入信息

点击Activity_01中得GO后

修改editText

点击Activity_02中的RESULT_OK

三. 细节

1.意图用来描述一个程序想要做些什么事情，在Intent类的数据结构中有两个重要的部分，Intent所采取的动作（Action）和Intent对数据的处理，意图就是动作和数据配对所产生的反应。

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