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常用控件：
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- TextView
- EditView
- Menu
- Button
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例子：Activity003
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MainActivity.java
package com.example.activity003;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;import android.widget.EditText;import android.widget.TextView;public class MainActivity extends Activity { private EditText num1Et; private EditText num2Et; private int num1; private int num2; private int result; private TextView menuStatusTv; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); num1Et = (EditText) this.findViewById(R.id.num1); num2Et = (EditText) this.findViewById(R.id.num2); TextView operationTv = (TextView) this.findViewById(R.id.operation); Button calcBut = (Button) this.findViewById(R.id.calc); menuStatusTv = (TextView) this.findViewById(R.id.menuStatus); menuStatusTv.setText("菜单未选择"); operationTv.setText(R.string.operation); calcBut.setText("计算"); // 以匿名类的方式为按钮添加监听 calcBut.setOnClickListener(new OnClickListener() { @Override public void onClick(View view) { String num1Str = num1Et.getText().toString(); String num2Str = num2Et.getText().toString(); try { num1 = Integer.parseInt(num1Str); } catch (NumberFormatException e) { num1 = 0; } try { num2 = Integer.parseInt(num2Str); } catch (NumberFormatException e) { num2 = 0; } // 计算 result = num1 * num2; // 将计算结果传递到ResultActivity中 Intent intent = new Intent(); intent.putExtra("result", num1 + " * " + num2 + " = " + result); intent.setClass(MainActivity.this, ResultActivity.class); MainActivity.this.startActivity(intent); } }); } @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); int group1 = 1; int group2 = 2; menu.add(group1, 11, 1, "About1"); menu.add(group1, 12, 2, "Exit1"); menu.add(group2, 21, 3, "About2"); menu.add(group2, 22, 4, "Exit2"); return true; } @Override public boolean onOptionsItemSelected(MenuItem item) { menuStatusTv.setText("您选择了 " + item.getTitle()); switch (item.getItemId()) { case 11: // do nothing break; case 12: finish(); break; case 21: // do nothing break; case 22: // do nothing break; } return super.onContextItemSelected(item); }}?ResultActivity.java
package com.example.activity003;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.view.Menu;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.TextView;public class ResultActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_result); TextView resultTv = (TextView) this.findViewById(R.id.result); Button backBut = (Button) this.findViewById(R.id.back); // 获取处理结果 Intent intent = this.getIntent(); String result = intent.getStringExtra("result"); resultTv.setText(result); backBut.setText("返回"); backBut.setOnClickListener(new OnClickListener() { @Override public void onClick(View view) { Intent intent = new Intent(); intent.setClass(ResultActivity.this, MainActivity.class); ResultActivity.this.startActivity(intent); } }); } @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; }}?res/layout/activity_main.xml
<LinearLayout 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:orientation="vertical" 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=".MainActivity" > <TextView android:id="@+id/menuStatus" android:layout_width="fill_parent" android:layout_height="wrap_content" /> <EditText android:id="@+id/num1" android:layout_width="fill_parent" android:layout_height="wrap_content" android:inputType="number" /> <TextView android:id="@+id/operation" android:layout_width="fill_parent" android:layout_height="wrap_content" /> <EditText android:id="@+id/num2" android:layout_width="fill_parent" android:layout_height="wrap_content" android:inputType="number" /> <Button android:id="@+id/calc" android:layout_width="fill_parent" android:layout_height="wrap_content" /></LinearLayout>
?res/layout/activity_result.xml
<LinearLayout 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:orientation="vertical" 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=".MainActivity" > <TextView android:id="@+id/result" android:layout_width="fill_parent" android:layout_height="wrap_content" /> <Button android:id="@+id/back" android:layout_width="fill_parent" android:layout_height="wrap_content" /></LinearLayout>
?res/values/strings.xml
<?xml version="1.0" encoding="utf-8"?><resources> <string name="app_name">Activity003</string> <string name="action_settings">Settings</string> <string name="hello_world">Hello world!</string> <string name="operation">乘以</string> <string name="activity_result">计算结果</string></resources>
?AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.activity003" android:versionCode="1" android:versionName="1.0" > <uses-sdk android:minSdkVersion="8" android:targetSdkVersion="9" /> <application android:allowBackup="true" android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" > <activity android:name="com.example.activity003.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=".ResultActivity" android:label="@string/activity_result" > </activity> </application></manifest>
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运行结果：
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