Android关于activityForResult

 这个是关于onActivityResult的例子——跳转传值的问题

从a页面跳往b页面

  @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        findViewById(R.id.btn).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
//                等同于下面的写法
//                Intent intent=new Intent(MainActivity.this,SecondActivity.class);
//                startActivityForResult(intent,1);
                startActivityForResult(new Intent(MainActivity.this,SecondActivity.class),1);
            }
        });
        textView=(TextView) findViewById(R.id.tv);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode==1&&resultCode==4){
            String str=data.getStringExtra("value");
            textView.setText(str);
        }else{
            Toast.makeText(MainActivity.this,"没有收到传值",Toast.LENGTH_SHORT).show();
        }
    }

从b页面再跳回来

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

           setContentView(R.layout.activity_second);

           et=(EditText) findViewById(R.id.et);
           btn2=findViewById(R.id.btn2);
           btn2.setOnClickListener(new View.OnClickListener() {
               @Override
               public void onClick(View v) {
                   Intent  intent=new Intent();
                   intent.putExtra("value",et.getText().toString().trim());
                   setResult(4,intent);
                   finish();
               }
           });
    }

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https://github.com/zxk199003/android_test1