activity如何传递数据:
package com.example.androidtest;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Intent it = getIntent();
System.out.println(it);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
打印出来的结果：
03-03 14:07:15.721: I/System.out(930):
Intent {
act=android.intent.action.MAIN
cat=[android.intent.category.LAUNCHER]
flg=0x10000000
cmp=com.example.androidtest/.MainActivity
}
这是不是就是安卓清单文件定义的：
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.androidtest"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="14"
android:targetSdkVersion="14" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
我们继续添加第二个Activity，看看两个活动如何跳转.
此时的activity_main.xml文件：
<RelativeLayout 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="com.example.androidtest.MainActivity" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/hello_world" />
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/buttontext" />
</RelativeLayout>
清单文件:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.androidtest"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="14"
android:targetSdkVersion="14" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".MainActivity"
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=".SecondActivity">
</activity>
</application>
</manifest>
从MainActivity.class启动：
package com.example.androidtest;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class MainActivity extends Activity {
private Button button;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button = (Button)findViewById(R.id.button1);
button.setOnClickListener(
new OnClickListener(){
@Override
public void onClick(View arg0) {
Intent intent = new Intent(MainActivity.this,SecondActivity.class);
//方式1:使用putExtra方法:
intent.putExtra("name","ssss");
intent.putExtra("age", 17);
startActivity(intent);
//方式2:使用putExtras方法:
/*
Bundle myBundelForName=new Bundle();
myBundelForName.putString("name","ssss");
myBundelForName.putString("age",17);
intent.putExtras(myBundelForName);
*/
}
}
);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
SecondActivity.java
package com.example.androidtest;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
public class SecondActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.second);
Intent it = getIntent();
//方式1
Log.i("secondactivity",it.getStringExtra("name"));
//方式2
Bundle bundle = it.getExtras();
bundle.get("name");
bundle.get("age");
//另外，既然bundle对象类似map,可以实现遍历
}
}
此时在SecondActivity中 System.out.println(it); 输出的内容是：
03-04 02:14:28.867: I/System.out(567): Intent { cmp=com.example.androidtest/.SecondActivity }
安卓文档上，对该方法的解释是:
Activity (Test API)
public Intent getIntent()
Return the intent that started this activity.
较好的传递数据的方法:
public static void actionStart(Context context,String data1,String data2){
Intent intent = new Intent(context,SecondActivity.class);
intent.putExtra("params1", data1);
intent.putExtra("params2", data2);
context.startActivity(intent);
}
这样，从任意的Activity启动SecondActivity都变得容易，要传递的数据也一目了然。如下:
SecondActivity.actionStart(FirstActivity.this,data1,data2);
