Activation and value transfer of activity

Activity Start of

 ①.  stay Android The communication between components in the application uses Intent. One Activity adopt Intent To express your “ Intention ”.

 ②.  There are usually two ways ：

- Intent intent = new Intent(MainActivity.this , NextActivity.class);

- Intent intent = new Intent();

- intent.setClass(MainActivity.this , NextActivity.class);

③. There are two common startup methods ：

- startActivity();

- startActivityForResult();// Use... When you need to return data

Activity Jump and exchange data between ：

① The data is transferred to the next page

from MainActivity Jump to FirstActivity The code is as follows

Intent intent =new Intent(MainActivity.this,FirstActivity.class);
// Pass string 
intent.putExtra("value1"," I'm from MainActivity The data that came in ");
intent.putExtra("value2",100);// Pass integer 
startActivity(intent);

//HashMap<String,String> map=new HashMap<String,String>();
//map.put("aaa"," I am a aaa");
//map.put("dddd"," I am a ddd");
//Intent intent2 =new Intent(MainActivity.this,FirstActivity.class);
//intent2.putExtra("map",map);// If it is javabean be bean Need to serialize 
//startActivity(intent2);

 

stay FirstActivity Data received in

String str=  intent.getStringExtra("value1");
int intValue= intent.getIntExtra("value2",0);

 

② Data back （SecondActivity Return data to MainActivity）

MainActivity Middle jump

Intent intent2 = new Intent(MainActivity.this, SecondActivity.class);

startActivityForResult(intent2, 1111);

rewrite onActivityResut receive data

   if (requestCode == 1111) {// And jumping requestCode  Corresponding 
            if(resultCode==RESULT_OK)
            {
               String str= data.getStringExtra("str");
                mTextView3.setText(str);
            }
        }

SecondActivity Set data in

   Intent intent=new Intent();
   intent.putExtra("str"," I am a SecondActivity Data returned from ");
   setResult(RESULT_OK,intent);
   finish();

 

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https://download.csdn.net/download/u010350891/10674585