Activity 跳转与返回

两个 Activity 跳转，都是在第一个 Activity 调用 startActivity() 方法启动第二个 Activity ，然后在第二个 Activity 调用 Context.finish() 方法实现返回到第一个 Activity 。但是有的时候业务需求很复杂，从第二个 Activity 返回到第一个 Activity 时候，需要再次处理某些事情时就要使用 startActivityForResult() 方法启动第二个 Activity 了，并在第一个 Activity 中重写 onActivityResult() 方法。

@Override

public void onCreate(Bundle savedInstanceState) {

          super.onCreate(savedInstanceState);

          setContentView(R.layout.main);

 

          btnLogin = (Button) findViewById(R.id.btnLogin);

          userid = (EditText) findViewById(R.id.userid);

          pwd = (EditText) findViewById(R.id.password);

 

          btnLogin.setOnClickListener(new View.OnClickListener() {

                   @Override

                   public void onClick(View v) {

                             if (userid.getText().toString().equals("tony")

                                               && pwd.getText().toString().equals("1")) {

                                      Intent it = new Intent(LoginActivity.this,

                                                         SuccessActivity.class);

                                      it.putExtra("userid", userid.getText().toString());

                                      startActivityForResult(it, 1);

                             } else {

                                      Intent it = new Intent(LoginActivity.this,

                                                         FailureActivity.class);

                                      startActivityForResult(it, 2);

                             }

                   }

          });

}

 

@Override

protected void onActivityResult(int requestCode, int resultCode, Intent data) {

          switch (requestCode) {

          case 1:

                   // 登录成功之后返回的。

                   Log.v(TAG, "from success activity return. resultCode=" + resultCode);

                   break;

          case 2:

                   // 登录失败之后返回的。

                   Log.v(TAG, "from failure activity return. resultCode=" + resultCode);

          }

          super.onActivityResult(requestCode, resultCode, data);

 

}

 

}

 

 

成功屏幕 SuccessActivity

 

public class SuccessActivity extends Activity {

 

Button btnBack;

TextView label;

 

@Override

protected void onCreate(Bundle savedInstanceState) {

          super.onCreate(savedInstanceState);

          setContentView(R.layout.success);

 

          label = (TextView) findViewById(R.id.label);

          Bundle bundle = this.getIntent().getExtras();

          String userid = bundle.getString("userid");

          label.setText(userid);

          btnBack = (Button) findViewById(R.id.btnBack);

          btnBack.setOnClickListener(new View.OnClickListener() {

 

                   @Override

                   public void onClick(View v) {

                             setResult(4, (new Intent()).putExtra("name", label.getText()

                                               .toString()));

                             SuccessActivity.this.finish();

                   }

          });

 

}

 

}

失败屏幕 FailureActivity

 

public class FailureActivity extends Activity {

 

Button btnBack ;

TextView label;

 

@Override

protected void onCreate(Bundle savedInstanceState) {

          super.onCreate(savedInstanceState);

          setContentView(R.layout.failure);

          label  = (TextView)findViewById(R.id.label);

          btnBack = (Button)findViewById(R.id.btnBack);

          btnBack.setOnClickListener(new View.OnClickListener() {

 

                   @Override

                   public void onClick(View v) {

                             setResult(5);

                             FailureActivity.this.finish();

                   }

          });

 

}

 

}