一个Android程序 Helloworld

HelloActivity.java

package mars.helloworld;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class HelloActivity extends Activity {
private Button myButton1 = null;
private Button myButton2 = null;
private TextView myEditText = null;
private TextView myTextView = null;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);//设置Activity的布局
myButton1 = (Button)findViewById(R.id.myButton1);//得到按钮对象s
myButton2 = (Button)findViewById(R.id.myButton2);
myEditText = (TextView)findViewById(R.id.myEditText);//得到TextView对象
myTextView = (TextView)findViewById(R.id.myTextView);
myButton1.setOnClickListener(new View.OnClickListener() {//给按钮注册监听器

public void onClick(View v) {
myTextView.setText(myEditText.getText());
}
});
myButton2.setOnClickListener(new View.OnClickListener() {

public void onClick(View v) {
myTextView.setText(new String());
}
});

}
}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="mars.helloworld"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="4" />

<application android:icon="@drawable/icon" android:label="@string/app_name">
<activity android:name=".HelloActivity"
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>

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/myEditText"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
<Button
android:id="@+id/myButton1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/myButtonText1"
/>
<Button
android:id="@+id/myButton2"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/myButtonText2"
/>
<TextView
android:id="@+id/myTextView"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
</LinearLayout>

strings.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="hello">Hello World, HelloActivity!</string>
<string name="app_name">helloworld</string>
<string name="myButtonText1">Click Button One</string>
<string name="myButtonText2">Click Button Two</string>
</resources>