Question

您好我正在尝试将2个字符串发送到另一个活动，但我收到空异常错误，这是我的第一个活动的代码：

Intent zistactivity = new Intent(reshte.this,List1.class);  
zistactivity.putExtra("url","http://api.safshari.com/test.json");
zistactivity.putExtra("daste", "zist");
startActivity(zistactivity);

我的第二项活动是：

String url = getIntent().getExtras().getString("url");
String daste = getIntent().getExtras().getString("daste");

和logcat：

06-26 13:36:20.323: E/AndroidRuntime(597): FATAL EXCEPTION: main
06-26 13:36:20.323: E/AndroidRuntime(597): Process: com.safshari.konkor, PID: 597
06-26 13:36:20.323: E/AndroidRuntime(597): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.safshari.konkor/com.safshari.konkor.List1}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.os.Bundle android.content.Intent.getExtras()' on a null object reference
06-26 13:36:20.323: E/AndroidRuntime(597):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2236)
06-26 13:36:20.323: E/AndroidRuntime(597):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
06-26 13:36:20.323: E/AndroidRuntime(597):  at android.app.ActivityThread.access$800(ActivityThread.java:151)
06-26 13:36:20.323: E/AndroidRuntime(597):  at  android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
06-26 13:36:20.323: E/AndroidRuntime(597):  at android.os.Handler.dispatchMessage(Handler.java:102)
06-26 13:36:20.323: E/AndroidRuntime(597):  at android.os.Looper.loop(Looper.java:135)
06-26 13:36:20.323: E/AndroidRuntime(597):  at android.app.ActivityThread.main(ActivityThread.java:5254)
06-26 13:36:20.323: E/AndroidRuntime(597):  at java.lang.reflect.Method.invoke(Native Method)
06-26 13:36:20.323: E/AndroidRuntime(597):  at java.lang.reflect.Method.invoke(Method.java:372)
06-26 13:36:20.323: E/AndroidRuntime(597):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
06-26 13:36:20.323: E/AndroidRuntime(597):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
06-26 13:36:20.323: E/AndroidRuntime(597): Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.os.Bundle android.content.Intent.getExtras()' on a null object reference
06-26 13:36:20.323: E/AndroidRuntime(597):  at com.safshari.konkor.List1.<init>(List1.java:32)
06-26 13:36:20.323: E/AndroidRuntime(597):  at java.lang.reflect.Constructor.newInstance(Native Method)
06-26 13:36:20.323: E/AndroidRuntime(597):  at java.lang.Class.newInstance(Class.java:1606)
06-26 13:36:20.323: E/AndroidRuntime(597):  at android.app.Instrumentation.newActivity(Instrumentation.java:1066)
06-26 13:36:20.323: E/AndroidRuntime(597):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2226)

Answer 1

在发件人活动中：

editPictureViewController

在接收者活动中：

Intent intent = new Intent(reshte.this,List1.class);
Bundle bundle = new Bundle();
bundle.putString("key1","value1");
(...)
intent.putExtras(bundle);
// Launch intent

试试吧。您必须将所有传递的数据放入一个包中，以获得更好的体验（至少在我看来）

Answer 2

如果声明了两个活动，请检查清单文件。参考日志：

06-26 13:36:20.323: E/AndroidRuntime(597): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.safshari.konkor/com.safshari.konkor.List1}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.os.Bundle android.content.Intent.getExtras()' on a null object reference

Answer 3

您使用Intent而不是Bundle发送字符串值。所以使用getStringExtra从获取值：

 Intent intent=this.getIntent();
    if(intent !=null)
     value = intent.getStringExtra("variable");

Answer 4

If you are putting extra directly, use get(Type)Extra instead.

Answer 5

Bundle bundle = getIntent().getExtras();
String url= bundle.getString("url");

//bundle contain all String data

getIntent.getExtras.getString（）中的null值

5 个答案: