问题
In my activity, I\'m calling a second activity from the main activity by startActivityForResult. In my second activity there are some methods that finish this activity (maybe without result), however, just one of them return a result.
For example, from the main activity I call a second one. In this activity I\'m checking some features of handset such as does it have a camera. If it doesn\'t have then I\'ll close this activity. Also, during preparation of MediaRecorder or MediaPlayer if a problem happens then I\'ll close this activity.
If its device has a camera and recording is done completely, then after recording a video if a user clicks on the done button then I\'ll send the result (address of the recorded video) back to main activity.
How do I check the result from the main activity?
回答1:
From your FirstActivity call the SecondActivity using startActivityForResult() method
For example:
Intent i = new Intent(this, SecondActivity.class);
startActivityForResult(i, 1);
In your SecondActivity set the data which you want to return back to FirstActivity. If you don't want to return back, don't set any.
For example: In SecondActivity if you want to send back data:
Intent returnIntent = new Intent();
returnIntent.putExtra("result",result);
setResult(Activity.RESULT_OK,returnIntent);
finish();
If you don't want to return data:
Intent returnIntent = new Intent();
setResult(Activity.RESULT_CANCELED, returnIntent);
finish();
Now in your FirstActivity class write following code for the onActivityResult() method.
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == 1) {
if(resultCode == Activity.RESULT_OK){
String result=data.getStringExtra("result");
}
if (resultCode == Activity.RESULT_CANCELED) {
//Write your code if there's no result
}
}
}//onActivityResult
回答2:
How to check the result from the main activity?
You need to override Activity.onActivityResult() then check its parameters:
requestCodeidentifies which app returned these results. This is defined by you when you callstartActivityForResult().resultCodeinforms you whether this app succeeded, failed, or something differentdataholds any information returned by this app. This may benull.
回答3:
Complementing the answer from @Nishant,the best way to return the activity result is:
Intent returnIntent = getIntent();
returnIntent.putExtra("result",result);
setResult(RESULT_OK,returnIntent);
finish();
I was having problem with
new Intent();
Then I found out that the correct way is using
getIntent();
to get the current intent
回答4:
Example
To see the entire process in context, here is a supplemental answer. See my fuller answer for more explanation.
MainActivity.java
public class MainActivity extends AppCompatActivity {
// Add a different request code for every activity you are starting from here
private static final int SECOND_ACTIVITY_REQUEST_CODE = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
// "Go to Second Activity" button click
public void onButtonClick(View view) {
// Start the SecondActivity
Intent intent = new Intent(this, SecondActivity.class);
startActivityForResult(intent, SECOND_ACTIVITY_REQUEST_CODE);
}
// This method is called when the second activity finishes
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
// check that it is the SecondActivity with an OK result
if (requestCode == SECOND_ACTIVITY_REQUEST_CODE) {
if (resultCode == RESULT_OK) { // Activity.RESULT_OK
// get String data from Intent
String returnString = data.getStringExtra("keyName");
// set text view with string
TextView textView = (TextView) findViewById(R.id.textView);
textView.setText(returnString);
}
}
}
}
SecondActivity.java
public class SecondActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_second);
}
// "Send text back" button click
public void onButtonClick(View view) {
// get the text from the EditText
EditText editText = (EditText) findViewById(R.id.editText);
String stringToPassBack = editText.getText().toString();
// put the String to pass back into an Intent and close this activity
Intent intent = new Intent();
intent.putExtra("keyName", stringToPassBack);
setResult(RESULT_OK, intent);
finish();
}
}
回答5:
For those who have problem with wrong requestCode in onActivityResult
If you are calling startActivityForResult() from your Fragment, the requestCode is changed by the Activity that owns the Fragment.
If you want to get the correct resultCode in your activity try this:
Change:
startActivityForResult(intent, 1); To:
getActivity().startActivityForResult(intent, 1);
回答6:
If you want to update the user interface with activity result, you can't to use this.runOnUiThread(new Runnable() {}
Doing this the UI won't refresh with new value. Instead, you can do this:
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == RESULT_CANCELED) {
return;
}
global_lat = data.getDoubleExtra("LATITUDE", 0);
global_lng = data.getDoubleExtra("LONGITUDE", 0);
new_latlng = true;
}
@Override
protected void onResume() {
super.onResume();
if(new_latlng)
{
PhysicalTagProperties.this.setLocation(global_lat, global_lng);
new_latlng=false;
}
}
This seems silly but works pretty well.
回答7:
First you use startActivityForResult() with parameters in first Activity and if you want to send data from second Activity to first Activity then pass value using Intent with setResult() method and get that data inside onActivityResult() method in first Activity.
回答8:
Very common problem in android
It can be broken down into 3 Pieces
1 ) start Activity B (Happens in Activity A)
2 ) Set requested data (Happens in activity B)
3 ) Receive requested data (Happens in activity A)
1) startActivity B
Intent i = new Intent(A.this, B.class);
startActivity(i);
2) Set requested data
In this part, you decide whether you want to send data back or not when a particular event occurs.
Eg: In activity B there is an EditText and two buttons b1, b2.
Clicking on Button b1 sends data back to activity A
Clicking on Button b2 does not send any data.
Sending data
b1......clickListener
{
Intent resultIntent = new Intent();
resultIntent.putExtra("Your_key","Your_value");
setResult(RES_CODE_A,resultIntent);
finish();
}
Not sending data
b2......clickListener
{
setResult(RES_CODE_B,new Intent());
finish();
}
user clicks back button
By default, the result is set with Activity.RESULT_CANCEL response code
3) Retrieve result
For that override onActivityResult method
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == RES_CODE_A) {
// b1 was clicked
String x = data.getStringExtra("RES_CODE_A");
}
else if(resultCode == RES_CODE_B){
// b2 was clicked
}
else{
// back button clicked
}
}
回答9:
You need to override Activity.onActivityResult()
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == RESULT_CODE_ONE) {
String a = data.getStringExtra("RESULT_CODE_ONE");
}
else if(resultCode == RESULT_CODE_TWO){
// b was clicked
}
else{
}
}
来源：https://stackoverflow.com/questions/10407159/how-to-manage-startactivityforresult-on-android