Android 全局变量 Application

╰+哭是因爲堅強的太久メ 2023-06-12 04:13 28阅读 0赞

**MainActivity**

public class MainActivity extends Activity { 
    
    	private Button button;
    	private MyApp myApp;
    	
    	@Override
    	protected void onCreate(Bundle savedInstanceState) { 
    		super.onCreate(savedInstanceState);
    		setContentView(R.layout.activity_main);
    				
    		button = (Button)this.findViewById(R.id.button);
    		myApp = (MyApp)getApplication();
    		
    		button.setOnClickListener(new View.OnClickListener() { 
    			
    			@Override
    			public void onClick(View v) { 
    				// TODO Auto-generated method stub
    				myApp.setName("thomas");
    				
    				Intent intent = new Intent(MainActivity.this, OtherActivity.class);
    				startActivity(intent);
    			}
    		});
    	}
    }

**MyApp**  
需要继承Application

public class MyApp extends Application { 
    
    	public String  name;
    
    	public String getName() { 
    		return name;
    	}
    
    	public void setName(String string) { 
    		this.name = string;
    	}
    	
    	@Override
    	public void onCreate() { 
    		// TODO Auto-generated method stub
    		super.onCreate();
    	
    		setName("张三");
    	}
    }

**OtherActivity**

public class OtherActivity extends Activity { 
    
    	private MyApp myApp;
    	private TextView textView;
    	
    	@Override
    	protected void onCreate(Bundle savedInstanceState) { 
    		// TODO Auto-generated method stub
    		super.onCreate(savedInstanceState);
    
    		setContentView(R.layout.other);
    		
    		textView = (TextView)this.findViewById(R.id.msg);
    		myApp = (MyApp)getApplication();
    		textView.setText("OtherActivity getName " + myApp.getName());
    	}
    }

**试验效果**  
![1][]

[1]: /images/20230531/b8b0c9ea49f24b6583ed9c72eddc443f.png