Activity（三）

常用控件

EditView、TextView、Button

设置layout，在fragment_main.xml配置控件

配置可编辑文本控件factorOne、factorTwo，显示文本控件symbol，按钮控件calculate

<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.activity01.MainActivity$PlaceholderFragment" >

    <EditText
        android:id="@+id/factorOne"
        android:layout_width="fill_parent"
         android:layout_height="wrap_content"/>
      <EditText
        android:id="@+id/factorTwo"
        android:layout_width="fill_parent"
         android:layout_height="wrap_content"
         android:layout_below="@+id/sym"/>
    <TextView
        android:id="@+id/sym"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/factorOne" />
    <Button
        android:id="@+id/cal"
         android:layout_width="fill_parent"
         android:layout_height="wrap_content"
          android:layout_below="@+id/factorTwo"
        />
</RelativeLayout>

在values下string.xml设置symbol、calculate字符串

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <string name="app_name">Activity01</string>
    <string name="hello_world">Hello world!</string>
    <string name="action_settings">Settings</string>
    <string name="sym">乘以</string>
    <string name="cal">计算</string>
</resources>

根据控件id取对象，为symbol和calculate设置显示的值

        private EditText factorOne=null;
    private EditText factorTwo=null;
    private TextView sym=null;
    private Button cal=null;
  @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);
        factorOne=(EditText)findViewById(R.id.factorOne);
        factorTwo=(EditText)findViewById(R.id.factorTwo);
        sym=(TextView)findViewById(R.id.sym);
        cal=(Button)findViewById(R.id.cal);
        sym.setText(R.string.sym);
        cal.setText(R.string.cal);
        cal.setOnClickListener(new CalListener());//监听器绑定到按钮上
        return true;
    }  

监听器

class CalListener implements OnClickListener{

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            String factorOneStr=factorOne.getText().toString();
            String factorTwoStr=factorTwo.getText().toString();
            Intent intent=new Intent();
            intent.putExtra("one", factorOneStr);
            intent.putExtra("two", factorTwoStr);
            intent.setClass(MainActivity.this, ResultActivity.class);
            MainActivity.this.startActivity(intent);
        }
    }

新建result.xml文件

     <TextView
        android:id="@+id/result"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
       />

新建ResultActivity，获取计算结果

public class ResultActivity extends Activity{
    private TextView resultView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.result);
        resultView=(TextView)findViewById(R.id.result);
        Intent intent=new Intent();
        String factorOneStr=intent.getStringExtra("one");
        String factorTwoStr=intent.getStringExtra("two");
        int factorOneInt=Integer.parseInt(factorOneStr);
        int factorTwoInt=Integer.parseInt(factorTwoStr);
        int result=factorOneInt * factorTwoInt;
        resultView.setText(result+"");
    }
}

注册ResultActivity

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.activity01"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="18" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.activity01.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="com.example.activity01.ResultActivity"
            android:label="@string/app_name" >
        </activity>
    </application>

</manifest>

设置menu菜单

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        menu.add(0, 1, 1, R.string.exit);
        menu.add(0, 2, 3, R.string.about);
        return super.onCreateOptionsMenu(menu);
    }
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // TODO Auto-generated method stub
        if(item.getItemId()==1){
            finish();
        }
        return super.onOptionsItemSelected(item);
    }