【Android(安卓)开发教程】使用Intent传递数据

本章节翻译自《Beginning-Android-4-Application-Development》，如有翻译不当的地方，敬请指出。

原书购买地址http://www.amazon.com/Beginning-Android-4-Application-Development/dp/1118199545/

除了能从一个Activity返回数据结果之外，向一个Activity传递数据也是很常用的。

1. 新建一个工程，PassData。

2. main.xml中的代码。

[java] view plain copy

<?xmlversion="1.0"encoding="utf-8"?>
<LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
<Button
android:id="@+id/btn_SecondActivity"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:onClick="onClick"
android:text="ClicktogotoSecondActivity"/>
</LinearLayout>

3. 在res/layout文件夹下，创建secondactivity.xml文件。 [java] view plain copy

<?xmlversion="1.0"encoding="utf-8"?>
<LinearLayoutxmlns: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:text="WelcometoSecondActivity"/>
<Button
android:id="@+id/btn_MainActivity"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:onClick="onClick"
android:text="Clicktoreturntomainactivity"/>
</LinearLayout>

4. 新建一个Activity子类：SecondActivity.java。 [java] view plain copy

publicclassSecondActivityextendsActivity{
@Override
publicvoidonCreate(BundlesavedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.secondactivity);
//---getthedatapassedinusinggetStringExtra()---
Toast.makeText(this,getIntent().getStringExtra("str1"),
Toast.LENGTH_SHORT).show();
//---getthedatapassedinusinggetIntExtra()---
Toast.makeText(this,
Integer.toString(getIntent().getIntExtra("age1",0)),
Toast.LENGTH_SHORT).show();
//---gettheBundleobjectpassedin---
Bundlebundle=getIntent().getExtras();
//---getthedatausingthegetString()---
Toast.makeText(this,bundle.getString("str2"),Toast.LENGTH_SHORT)
.show();
//---getthedatausingthegetInt()method---
Toast.makeText(this,Integer.toString(bundle.getInt("age2")),
Toast.LENGTH_SHORT).show();
}
publicvoidonClick(Viewview){
//---useanIntentobjecttoreturndata---
Intenti=newIntent();
//---usetheputExtra()methodtoreturnsome
//value---
i.putExtra("age3",45);
//---usethesetData()methodtoreturnsomevalue---
i.setData(Uri.parse("Somethingpassedbacktomainactivity"));
//---settheresultwithOKandtheIntentobject---
setResult(RESULT_OK,i);
//---destroythecurrentactivity---
finish();
}
}

5. AndroidManifest.xml中的代码。 [java] view plain copy

<?xmlversion="1.0"encoding="utf-8"?>
<manifestxmlns:android="http://schemas.android.com/apk/res/android"
package="net.horsttnann.PassingData"
android:versionCode="1"
android:versionName="1.0">
<uses-sdkandroid:minSdkVersion="10"/>
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name">
<activity
android:name=".PassingDataActivity"
android:label="@string/app_name">
<intent-filter>
<actionandroid:name="android.intent.action.MAIN"/>
<categoryandroid:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
<activity
android:name="net.manoel.PassingData.SecondActivity"
android:label="SecondActivity">
<intent-filter>
<actionandroid:name="net.horsttnann.PassingDataSecondActivity"/>
<categoryandroid:name="android.intent.category.DEFAULT"/>
</intent-filter>
</activity>
</application>
</manifest>

6. PassDataActivity中的代码。

public class PassingDataActivity extends Activity {    /** Called when the activity is first created. */    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);    }        public void onClick(View view) {    Intent i = new     Intent("net.manoel.PassingDataSecondActivity");    //---use putExtra() to add new key/value pairs---                i.putExtra("str1", "This is a string");    i.putExtra("age1", 25);    //---use a Bundle object to add new key/values     // pairs---      Bundle extras = new Bundle();    extras.putString("str2", "This is another string");    extras.putInt("age2", 35);                    //---attach the Bundle object to the Intent object---    i.putExtras(extras);                    //---start the activity to get a result back---    startActivityForResult(i, 1);    }        public void onActivityResult(int requestCode,     int resultCode, Intent data)    {        //---check if the request code is 1---        if (requestCode == 1) {            //---if the result is OK---             if (resultCode == RESULT_OK) {                //---get the result using getIntExtra()---                Toast.makeText(this, Integer.toString(                    data.getIntExtra("age3", 0)),                     Toast.LENGTH_SHORT).show();                      //---get the result using getData()---                Toast.makeText(this, data.getData().toString(),                     Toast.LENGTH_SHORT).show();            }                    }    }}

7. 按F11调试。

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