发送一个字符串从一个活动到另一个

Question

EDITED为了让你保持最新状态。

感谢您的答案。试了一下，但没有解决问题。 字符串和名称是正确的。 （选择一个是我想发送的字符串，另一个是名称）。

我今天花了几个小时玩代码，仍然崩溃......（解决了一些错误）。

这是从活动2：

// The on-click listener for all devices in the ListViews 
private OnItemClickListener mDeviceClickListener = new OnItemClickListener() { 
    public void onItemClick(AdapterView<?> av, View v, int arg2, long arg3) { 
     // Cancel discovery because it's costly and we're about to connect 
     mBluetoothAdapter.cancelDiscovery(); 

     /*Send string to the other activity */ 
     String chosenone = ((TextView) v).getText().toString(); 
     Intent intent = new Intent(); 
     intent.putExtra("theotherdude", chosenone); 
     toasttest(chosenone); 

     /*To avoid it from going back with nothing*/ 
     if(chosenone != null){ 
      // Set result and finish this Activity 
      setResult(Activity.RESULT_OK, intent); 
      finish(); 
     } 
    } 
}; 

和活动1：

public void onActivityResult(int requestCode, int resultCode, Intent data) { 
    super.onActivityResult(requestCode, resultCode, data); 
    // Check which request we're responding to 
    if (requestCode == MY_REQUEST) { 
     // Make sure the request was successful 
     if (resultCode == RESULT_OK) { 
      //String theotherdude = fromtheother.getString("theotherdude"); 
      Intent intent = getIntent(); 
      String id = intent.getStringExtra("theotherdude"); 

      // Get the device MAC address, which is the last 17 chars in the View 
      String address = id.substring(id.length() - 17); 
      String name = id.substring(0, id.length() - 17); 

      otherDeviceName.setText(R.string.with + name); 
      Toast.makeText(this, address, Toast.LENGTH_SHORT).show(); 
      } 
    } 
} 

logcat的：从

05-28 19:46:24.625: I/Process(19972): Sending signal. PID: 19972 SIG: 9 
05-28 19:48:55.086: D/libEGL(20267): loaded /vendor/lib/egl/libEGL_POWERVR_SGX540_120.so 
05-28 19:48:55.094: D/libEGL(20267): loaded /vendor/lib/egl/libGLESv1_CM_POWERVR_SGX540_120.so 
05-28 19:48:55.094: D/libEGL(20267): loaded /vendor/lib/egl/libGLESv2_POWERVR_SGX540_120.so 
05-28 19:48:55.188: D/OpenGLRenderer(20267): Enabling debug mode 0 
05-28 19:48:58.281: D/OpenGLRenderer(20267): Flushing caches (mode 0) 
05-28 19:49:00.688: D/AndroidRuntime(20267): Shutting down VM 
05-28 19:49:00.688: W/dalvikvm(20267): threadid=1: thread exiting with uncaught exception (group=0x40bec1f8) 
05-28 19:49:00.688: E/AndroidRuntime(20267): FATAL EXCEPTION: main 
05-28 19:49:00.688: E/AndroidRuntime(20267): java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=0, result=-1, data=Intent { (has extras) }} to activity {com.andrecl.interapption/com.andrecl.interapption.MainActivity}: java.lang.NullPointerException 
05-28 19:49:00.688: E/AndroidRuntime(20267): at android.app.ActivityThread.deliverResults(ActivityThread.java:2994) 
05-28 19:49:00.688: E/AndroidRuntime(20267): at android.app.ActivityThread.handleSendResult(ActivityThread.java:3037) 
05-28 19:49:00.688: E/AndroidRuntime(20267): at android.app.ActivityThread.access$1100(ActivityThread.java:128) 
05-28 19:49:00.688: E/AndroidRuntime(20267): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1191) 
05-28 19:49:00.688: E/AndroidRuntime(20267): at android.os.Handler.dispatchMessage(Handler.java:99) 
05-28 19:49:00.688: E/AndroidRuntime(20267): at android.os.Looper.loop(Looper.java:137) 
05-28 19:49:00.688: E/AndroidRuntime(20267): at android.app.ActivityThread.main(ActivityThread.java:4514) 
05-28 19:49:00.688: E/AndroidRuntime(20267): at java.lang.reflect.Method.invokeNative(Native Method) 
05-28 19:49:00.688: E/AndroidRuntime(20267): at java.lang.reflect.Method.invoke(Method.java:511) 
05-28 19:49:00.688: E/AndroidRuntime(20267): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790) 
05-28 19:49:00.688: E/AndroidRuntime(20267): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557) 
05-28 19:49:00.688: E/AndroidRuntime(20267): at dalvik.system.NativeStart.main(Native Method) 
05-28 19:49:00.688: E/AndroidRuntime(20267): Caused by: java.lang.NullPointerException 
05-28 19:49:00.688: E/AndroidRuntime(20267): at com.andrecl.interapption.MainActivity.onActivityResult(MainActivity.java:113) 
05-28 19:49:00.688: E/AndroidRuntime(20267): at android.app.Activity.dispatchActivityResult(Activity.java:4649) 
05-28 19:49:00.688: E/AndroidRuntime(20267): at android.app.ActivityThread.deliverResults(ActivityThread.java:2990) 
05-28 19:49:00.688: E/AndroidRuntime(20267): ... 11 more 
05-28 19:49:11.719: I/Process(20267): Sending signal. PID: 20267 SIG: 9 

如果删除了getextras（）和GetString（）线活动1它不会崩溃。问题能在那里吗？ 在我看来，就像它不会发送任何东西的主要活动......再次

感谢，

Answer 1

你的字符串是在Intent数据

public void onActivityResult(int requestCode, int resultCode, Intent data) { 
super.onActivityResult(requestCode, resultCode, data); 
/*Make sure we got the right device */ 
String EXTRA_DEVICE_ADDRESS = data.getStringExtra("theotherdude"); 

// Get the device MAC address, which is the last 17 chars in the View 
String address = EXTRA_DEVICE_ADDRESS.substring(EXTRA_DEVICE_ADDRESS.length() - 17); 
String name = EXTRA_DEVICE_ADDRESS.substring(0, EXTRA_DEVICE_ADDRESS.length() - 17); 

otherDeviceName.setText(R.string.with + name); 
Toast.makeText(this, address, Toast.LENGTH_SHORT).show(); 
} 

Answer 2

你没有得到正确的Intent在您的activity1。更改，上面写着

Bundle fromtheother = getIntent().getExtras(); 

到

Bundle fromtheother = data.getExtras(); 

data是Intent是activity2将返回行。

Answer 3

您正在以错误的方式检索数据。

intent.putExtra(EXTRA_DEVICE_ADDRESS, chosenone); 

格式：如果

intent.putExtra("StringReference",data); 

这里，EXTRA_DEVICE_ADDRESS实际上String是你应该检索数据的参考。

所以从技术上讲，你的第一个活动代码将是：

String EXTRA_DEVICE_ADDRESS = intent1.getExtras().getString("EXTRA_DEVICE_ADDRESS"); 

现在，校正。

intent.putExtra("chosenone", EXTRA_DEVICE_ADDRESS); 

第一项活动：

String EXTRA_DEVICE_ADDRESS = intent1.getExtras().getString("chosenone");