Android学习笔记-EditText&TextView&Button&菜单栏

界面文件activity_main.xml

< 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.activity_03.MainActivity"  >

    < EditText
        android:id = "@+id/factor_one"
        android:layout_width = "fill_parent"
        android:layout_height = "wrap_content"  />

    < TextView
        android:id = "@+id/symbol"
        android:layout_width = "fill_parent"
        android:layout_height = "wrap_content"
        android:layout_below = "@+id/factor_one"  />

    < EditText
        android:id = "@+id/factor_two"
        android:layout_width = "fill_parent"
        android:layout_height = "wrap_content"
        android:layout_below = "@+id/symbol"  />

    < Button
        android:id = "@+id/multiply"
        android:layout_width = "fill_parent"
        android:layout_height = "wrap_content"
        android:layout_below = "@+id/factor_two"  />

</ RelativeLayout >

界面文件result.xml

<? xml  version = "1.0"  encoding = "utf-8" ?>
< LinearLayout  xmlns:android = "http://schemas.android.com/apk/res/android"
    android:layout_width = "match_parent"
    android:layout_height = "match_parent"
    android:orientation = "vertical"  >

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

MainActivity.java

public  class  MainActivity  extends  ActionBarActivity {

    private  EditText factor_one;
    private  EditText factor_two;
    private  TextView symbol;
    private  Button multiply;
    @Override
    protected  void  onCreate(Bundle savedInstanceState) {
        super .onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        factor_one = (EditText) findViewById(R.id.factor_one);
        factor_two = (EditText) findViewById(R.id.factor_two);
        symbol = (TextView) findViewById(R.id.symbol);
        multiply = (Button) findViewById(R.id.multiply);

        symbol.setText(R.string.symbol);
        multiply.setText( "计算" );

        multiply.setOnClickListener( new  OnClickListener() {

            @Override
            public  void  onClick(View v) {
                // TODO Auto-generated method stub
                String factor_one_str = factor_one.getText().toString();
                String factor_two_str = factor_two.getText().toString();

                Intent intent =  new  Intent();
                intent.putExtra( "factor_one_str" , factor_one_str);
                intent.putExtra( "factor_two_str" , factor_two_str);

                intent.setClass(MainActivity. this , ResultActivity. class );
                MainActivity. this .startActivity(intent);
            }
        });
    }


    @Override
    public  boolean  onCreateOptionsMenu(Menu menu) { //设置菜单
        //MenuItem android.view.Menu.add(int groupId, int itemId, int order, int titleRes)
        menu.add( 0 ,  1 ,  1 , R.string.about);
        menu.add( 0 ,  2 ,  2 , R.string.exit);
        return  super .onCreateOptionsMenu(menu);
    }

    @Override
    public  boolean  onOptionsItemSelected(MenuItem item) { //选中菜单选项之后进行的操作
        if  (item.getItemId() ==  1 ) { //关于

        } else  if  (item.getItemId() ==  2 ) { //退出
            finish();
        }
        return  super .onOptionsItemSelected(item);
    }

}

ResultActivity.java

public  class  ResultActivity  extends  Activity{

    private  TextView result;

    @Override
    protected  void  onCreate(Bundle savedInstanceState) {
        super .onCreate(savedInstanceState);
        setContentView(R.layout.result);
        String factor_one_str = getIntent().getStringExtra( "factor_one_str" );
        String factor_two_str = getIntent().getStringExtra( "factor_two_str" );

        int  factor_one = Integer.parseInt(factor_one_str);
        int  factor_two = Integer.parseInt(factor_two_str);

        result = (TextView) findViewById(R.id.result);
        result.setText(factor_one * factor_two +  "" );
    }
}

strings.xml

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

    < string  name = "app_name" >Activity_03</ string >
    < string  name = "hello_world" >Hello world!</ string >
    < string  name = "action_settings" >Settings</ string >
    < string  name = "symbol" >乘以</ string >
    < string  name = "exit" >退出</ string >
    < string  name = "about" >关于</ string >
</ resources >

AndroidManifest.xml 中注册Activity

< activity  android:name = ".ResultActivity"  android:label = "ResultActivity" />

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