Android学习笔记_Activity初步

Activity初步
1.继承类Activity
2.重写onCreate()方法
3.每一个Activity都要在AndroidManifest.xml中进行配置
4.在Activity上添加控件
例：
public class MyActivity extends Activity{
    @Override
    public void onCreate(Bundle savedInstanceState){
       super.onCreate(savedInstanceState);
       setContentView(R.layout.main);
       TextView myTextView =(TextView)findViewById(R.id.myTextView);
       Button myButton =(Button)findViewById(R.id.myButton);
       myTextView.setText("我的第一个TextView");
       myButton.setText("我的第一个Button");
    }
}

多个Activity之间的关系
1.跳转
方法：startActivity(Intent intent)
一个Intent对象包含一组信息:
1.Component name
2.Action
3.Data
4.Category
5.Extras
6.Flags

Activity之间的跳转
public class Activity02 extends Activity{
    private Button myButton=null;
    public void onCreate(Bundle saveInstanceState){
        super.onCreate(saveInstanceState);
        setContentView(R.layout.main);
        myButton=(Button)findViewById(R.id.myButton);
        myButton.setOnClickListener(new MyButtonListener());
    }
    class MyButtonListener implements OnClickListener{
        public void onClick(View v){
            Intent intent=new Intent();
            intent.putExtra("testIntent","123");//传递数据
            intent.setClass(Activity02.this,OtherActivity.class);
            Activity02.this.startActivity(intent);
        }
    }
}


public class OtherActivity extends Activity{
     private TextView myTextView=null;
     protected void onCreate(Bundle saveInstanceState){
        super.onCreate(saveInstanceState);
        setContentView(R.layout.main);
        Intent intent=getIntent();
        String value=intent.getStringExtra("testIntent");//取出数据
        myTextView=(TextView)findViewById(R.id.myTextView);
        //myTextView.setText(R.string.other);
        myTextView.setText(value);
     }

}