Java 我可以在finish（）上传递一个额外的意图吗？

我想知道，调用finish（）后是否可以将信息发送到返回的活动

例如，我有一个Activity

SendMessageActivity.class

，它允许用户将消息发布到他们的提要。将该消息保存到服务器后，我调用

finish（）

。我是否应该以新的意图开始我的

main活动.class

？或者生命周期开发最好只完成

SendMessageActivity.class

我不认为启动新活动有什么意义，因为关闭当前活动总是会让您返回到

MainActivity.class

。如何在完成当前活动后发送一个额外的字符串？

您可以选择一个活动的名称，它允许您将数据输入到initent中

在第一个活动中，使用方法onActivityResult调用新活动并检索数据。所有内容都在文档中。

如果调用finish（）以避免用户返回SendMessageActivity.class，则可以将此标志设置为您的意图：

intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_CLEAR_TASK | Intent.FLAG_ACTIVITY_NEW_TASK);

这将打开MainActivity并从activities堆栈中删除SendMessageActivity。

尝试以下操作：

在第一项活动中：

Intent first = new Intent(ActivityA,this, ActivityB.class);
startActivityForResult(first, 1);

现在进入第二个活动：在

完成过程中设置结果（）

第一个活动捕捉结果

protected void onActivityResult(int requestCode, int resultCode, Intent data)  
   {  
     super.onActivityResult(requestCode, resultCode, data);  
      // check if the request code is same as what is passed  here it is 1  
       if(requestCode==1)  
             {  
                String message=data.getStringExtra("result");   
                //get the result
             }  
 }  

在ActivityResult上使用

这可能有助于您了解活动结果

通过使用
startActivityForResult（Intent-Intent，int-requestCode）
您可以启动另一个活动，然后在
onActivityResult（）
方法中从该活动接收结果。因此
onActivityResult（）
是从您启动另一个活动的地方开始的

onActivityResult（int-requestCode、int-resultCode、Intent-data）
检查此处的参数。请求代码用于过滤从何处获得结果。因此，您可以使用请求代码识别不同的数据

示例

 public class MainActivity extends Activity {

        // Use a unique request code for each use case 
        private static final int REQUEST_CODE_EXAMPLE = 0x9988; 

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);

            // Create an Intent to start AnotherActivity
            final Intent intent = new Intent(this, AnotherActivity.class);

            // Start AnotherActivity with the request code
            startActivityForResult(intent, REQUEST_CODE_EXAMPLE);
        }

        //-------- When a result is returned from another Activity onActivityResult is called.--------- //
        @Override
        public void onActivityResult(int requestCode, int resultCode, Intent data) {
            super.onActivityResult(requestCode, resultCode, data);

            // First we need to check if the requestCode matches the one we used.
            if(requestCode == REQUEST_CODE_EXAMPLE) {

                // The resultCode is set by the AnotherActivity
                // By convention RESULT_OK means that what ever
                // AnotherActivity did was successful
                if(resultCode == Activity.RESULT_OK) {
                    // Get the result from the returned Intent
                    final String result = data.getStringExtra(AnotherActivity.EXTRA_DATA);

                    // Use the data - in this case, display it in a Toast.
                    Toast.makeText(this, "Result: " + result, Toast.LENGTH_LONG).show();
                } else {
                    // AnotherActivity was not successful. No data to retrieve.
                }
            }
        }
    }

AnotherActivity
是否有与子活动等效的onActivityResult（）函数？我假设它的调用类似于onActivityRequest（），并且它允许我根据启动活动所调用的请求代码执行某些操作。
 public class MainActivity extends Activity {

        // Use a unique request code for each use case 
        private static final int REQUEST_CODE_EXAMPLE = 0x9988; 

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);

            // Create an Intent to start AnotherActivity
            final Intent intent = new Intent(this, AnotherActivity.class);

            // Start AnotherActivity with the request code
            startActivityForResult(intent, REQUEST_CODE_EXAMPLE);
        }

        //-------- When a result is returned from another Activity onActivityResult is called.--------- //
        @Override
        public void onActivityResult(int requestCode, int resultCode, Intent data) {
            super.onActivityResult(requestCode, resultCode, data);

            // First we need to check if the requestCode matches the one we used.
            if(requestCode == REQUEST_CODE_EXAMPLE) {

                // The resultCode is set by the AnotherActivity
                // By convention RESULT_OK means that what ever
                // AnotherActivity did was successful
                if(resultCode == Activity.RESULT_OK) {
                    // Get the result from the returned Intent
                    final String result = data.getStringExtra(AnotherActivity.EXTRA_DATA);

                    // Use the data - in this case, display it in a Toast.
                    Toast.makeText(this, "Result: " + result, Toast.LENGTH_LONG).show();
                } else {
                    // AnotherActivity was not successful. No data to retrieve.
                }
            }
        }
    }

public class AnotherActivity extends Activity {

        // Constant used to identify data sent between Activities.
        public static final String EXTRA_DATA = "EXTRA_DATA";

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_another);

            final View button = findViewById(R.id.button);
            // When this button is clicked we want to return a result
            button.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    // Create a new Intent as container for the result
                    final Intent data = new Intent();

                    // Add the required data to be returned to the MainActivity
                    data.putExtra(EXTRA_DATA, "Some interesting data!");

                    // Set the resultCode to Activity.RESULT_OK to 
                    // indicate a success and attach the Intent
                    // which contains our result data
                    setResult(Activity.RESULT_OK, data); 

                    // With finish() we close the AnotherActivity to 
                    // return to MainActivity
                    finish();
                }
            });
        }

        @Override
        public void onBackPressed() {
            // When the user hits the back button set the resultCode 
            // to Activity.RESULT_CANCELED to indicate a failure
            setResult(Activity.RESULT_CANCELED);
            super.onBackPressed();
        }
    }