Question

在这种情况下，两个活动A和B应该以A为结果调用B的方式进行交互。

但A从来没有从B获得任何数据。

此代码看起来像我见过的任何教程或SO问题。

调试会话确认调用了setResult。

这个问题让我失去了动力，如果有人能指出我所缺少的东西会很好。

编辑：代码在我的物理目标设备上执行时不起作用，但在nexus 5设备上运行查找。我能找到什么来找出原因？

MainActivity.java

package iifym.apps.rnoennig.de.myapplication;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;

public class MainActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);
    }

    public void onClick(View view) {
        Intent in = new Intent(this, SecondActivity.class);
        in.putExtra("mau", "bar");
        startActivityForResult(in, 1);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        // data is null ;(
        Toast.makeText(this, String.valueOf(data), Toast.LENGTH_SHORT).show();
    }
}

SecondActivity.java

package iifym.apps.rnoennig.de.myapplication;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;

public class SecondActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.second);

        Toast.makeText(this, String.valueOf(getIntent()), Toast.LENGTH_SHORT).show();
    }

    public void onClick(View view) {
        setResult(RESULT_OK, new Intent().putExtra("foo", "bar"));
        finish();
    }
}

布局/ main.xml中

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="New Button"
        android:id="@+id/button"
        android:layout_gravity="center_horizontal"
        android:onClick="onClick"
        />
</LinearLayout>

布局/ second.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="New Button"
        android:id="@+id/button2"
        android:layout_gravity="center_horizontal"
        android:onClick="onClick"
        />
</LinearLayout>

的AndroidManifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="iifym.apps.rnoennig.de.myapplication">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">

        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".SecondActivity"></activity>

    </application>

</manifest>

Answer 1

适合我。（相同的布局和清单）。

主要

public class MainActivity extends AppCompatActivity {

    public static final int MAIN_REQUEST = 1;

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

    public void onClick(View v) {
        Intent in = new Intent(MainActivity.this, SecondActivity.class);
        in.putExtra("mau", "start 2nd");
        startActivityForResult(in, MAIN_REQUEST);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == MAIN_REQUEST) {
            if (resultCode == RESULT_OK) {
                Toast.makeText(MainActivity.this, data.getStringExtra("foo"), Toast.LENGTH_SHORT).show();
            }
        }
    }
}

第二

public class SecondActivity extends AppCompatActivity {

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

        Intent sent = getIntent();
        if (sent != null) {
            Toast.makeText(SecondActivity.this, sent.getStringExtra("mau"), Toast.LENGTH_SHORT).show();
        }
    }

    public void onClick(View v) {
        setResult(RESULT_OK,  new Intent().putExtra("foo", "finish 2nd"));
        finish();
    }
}

onActivityResult产生null Intent

1 个答案: