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; @Override public 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:TEXT startActivityForResult(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 @Override protected 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 { @Override public 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:TEXT Bundle 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:TEXT intent.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 // tCode是RESULT_OK finish(); // 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。