致命异常主要 - startActivity

时间：2014-04-03 19:47:08

标签： java android eclipse

我是Android / Java的全新人物。我正在尝试创建一个应用程序，它将连接到我的TCP服务器以从mySQL获取数据。

我有以下内容：MainActivity - 这是登录屏幕。输入用户名和密码后，我连接到我的服务器

->startService(new Intent(this, tcpConnectionService.class));

服务器验证用户+ pwd，然后向我发送回复。 我正在分析响应，如果没问题，我想打开新的活动 - 对于某些数据请求。

static public void LOGIN_RESPONSE (String data)
{
    Toast.makeText(mainContext, data, Toast.LENGTH_LONG).show();
    //open search activity
    if (data.equals("LOGIN_OK"))
        mainContext.startActivity(new Intent(null, sn_search.class));
}

但不幸的是，我得到了例外...... 

04-03 19:05:11.008: E/AndroidRuntime(807): FATAL EXCEPTION: main
04-03 19:05:11.008: E/AndroidRuntime(807): java.lang.IllegalStateException: Could not execute method of the activity
04-03 19:05:11.008: E/AndroidRuntime(807):  at android.view.View$1.onClick(View.java:2144)
04-03 19:05:11.008: E/AndroidRuntime(807):  at android.view.View.performClick(View.java:2485)
04-03 19:05:11.008: E/AndroidRuntime(807):  at android.view.View$PerformClick.run(View.java:9080)
04-03 19:05:11.008: E/AndroidRuntime(807):  at android.os.Handler.handleCallback(Handler.java:587)
04-03 19:05:11.008: E/AndroidRuntime(807):  at android.os.Handler.dispatchMessage(Handler.java:92)
04-03 19:05:11.008: E/AndroidRuntime(807):  at android.os.Looper.loop(Looper.java:123)
04-03 19:05:11.008: E/AndroidRuntime(807):  at android.app.ActivityThread.main(ActivityThread.java:3683)
04-03 19:05:11.008: E/AndroidRuntime(807):  at java.lang.reflect.Method.invokeNative(Native Method)
04-03 19:05:11.008: E/AndroidRuntime(807):  at java.lang.reflect.Method.invoke(Method.java:507)
04-03 19:05:11.008: E/AndroidRuntime(807):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
04-03 19:05:11.008: E/AndroidRuntime(807):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
04-03 19:05:11.008: E/AndroidRuntime(807):  at dalvik.system.NativeStart.main(Native Method)
04-03 19:05:11.008: E/AndroidRuntime(807): Caused by: java.lang.reflect.InvocationTargetException
04-03 19:05:11.008: E/AndroidRuntime(807):  at java.lang.reflect.Method.invokeNative(Native Method)
04-03 19:05:11.008: E/AndroidRuntime(807):  at java.lang.reflect.Method.invoke(Method.java:507)
04-03 19:05:11.008: E/AndroidRuntime(807):  at android.view.View$1.onClick(View.java:2139)
04-03 19:05:11.008: E/AndroidRuntime(807):  ... 11 more
04-03 19:05:11.008: E/AndroidRuntime(807): Caused by: android.util.AndroidRuntimeException: Calling startActivity() from outside of an Activity  context requires the FLAG_ACTIVITY_NEW_TASK flag. Is this really what you want?
04-03 19:05:11.008: E/AndroidRuntime(807):  at android.app.ContextImpl.startActivity(ContextImpl.java:621)
04-03 19:05:11.008: E/AndroidRuntime(807):  at android.content.ContextWrapper.startActivity(ContextWrapper.java:258)
04-03 19:05:11.008: E/AndroidRuntime(807):  at kushnir.mkssql.MainActivity.LOGIN_RESPONSE(MainActivity.java:84)
04-03 19:05:11.008: E/AndroidRuntime(807):  at kushnir.mkssql.MainActivity.onClick(MainActivity.java:59)
04-03 19:05:11.008: E/AndroidRuntime(807):  ... 14 more
04-03 19:38:53.818: E/AndroidRuntime(3311): FATAL EXCEPTION: main
04-03 19:38:53.818: E/AndroidRuntime(3311): java.lang.IllegalStateException: Could not execute method of the activity
04-03 19:38:53.818: E/AndroidRuntime(3311):     at android.view.View$1.onClick(View.java:2144)
04-03 19:38:53.818: E/AndroidRuntime(3311):     at android.view.View.performClick(View.java:2485)
04-03 19:38:53.818: E/AndroidRuntime(3311):     at android.view.View$PerformClick.run(View.java:9080)
04-03 19:38:53.818: E/AndroidRuntime(3311):     at android.os.Handler.handleCallback(Handler.java:587)
04-03 19:38:53.818: E/AndroidRuntime(3311):     at android.os.Handler.dispatchMessage(Handler.java:92)
04-03 19:38:53.818: E/AndroidRuntime(3311):     at android.os.Looper.loop(Looper.java:123)
04-03 19:38:53.818: E/AndroidRuntime(3311):     at android.app.ActivityThread.main(ActivityThread.java:3683)
04-03 19:38:53.818: E/AndroidRuntime(3311):     at java.lang.reflect.Method.invokeNative(Native Method)
04-03 19:38:53.818: E/AndroidRuntime(3311):     at java.lang.reflect.Method.invoke(Method.java:507)
04-03 19:38:53.818: E/AndroidRuntime(3311):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
04-03 19:38:53.818: E/AndroidRuntime(3311):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
04-03 19:38:53.818: E/AndroidRuntime(3311):     at dalvik.system.NativeStart.main(Native Method)
04-03 19:38:53.818: E/AndroidRuntime(3311): Caused by: java.lang.reflect.InvocationTargetException
04-03 19:38:53.818: E/AndroidRuntime(3311):     at java.lang.reflect.Method.invokeNative(Native Method)
04-03 19:38:53.818: E/AndroidRuntime(3311):     at java.lang.reflect.Method.invoke(Method.java:507)
04-03 19:38:53.818: E/AndroidRuntime(3311):     at android.view.View$1.onClick(View.java:2139)
04-03 19:38:53.818: E/AndroidRuntime(3311):     ... 11 more
04-03 19:38:53.818: E/AndroidRuntime(3311): Caused by: java.lang.NullPointerException
04-03 19:38:53.818: E/AndroidRuntime(3311):     at android.content.ComponentName.<init>(ComponentName.java:75)
04-03 19:38:53.818: E/AndroidRuntime(3311):     at android.content.Intent.<init>(Intent.java:2702)
04-03 19:38:53.818: E/AndroidRuntime(3311):     at kushnir.mkssql.MainActivity.LOGIN_RESPONSE(MainActivity.java:82)
04-03 19:38:53.818: E/AndroidRuntime(3311):     at kushnir.mkssql.MainActivity.onClick(MainActivity.java:57)
04-03 19:38:53.818: E/AndroidRuntime(3311):     ... 14 more

3 个答案:

答案 0 :(得分：1)

new Intent(null, sn_search.class)

为何空？您应该指定上下文。

查看您的异常，它会告诉您问题所在：

Caused by: java.lang.NullPointerException
 at android.content.ComponentName.<init>(ComponentName.java:75)
 at android.content.Intent.<init>(Intent.java:2702)

Intent的构造函数引发了NullPointerException。猜猜为什么：）

答案 1 :(得分：0)

在开始活动之前，只需将其添加到意图中：intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

答案 2 :(得分：0)

在此电话会议中：

mainContext.startActivity(new Intent(null, sn_search.class));

mainContext必须是Activity;将其设置为getApplicationContext()会使其变为Context而不是Activity，这会导致异常。要解决此问题，请在mainContext类的正文中的某处将this（或其他某个字段）设置为Activity。如果startActivity调用本身发生在Activity类（或Fragment类）的主体内，则根本不需要对象;这很好：

startActivity(new Intent(null, sn_search.class));

（但可能需要使用Activity而不是null作为new Intent的第一个参数;似乎有两个异常从您的应用中抛出。）< / p>

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