2

我正在设计一个发送邮件的应用程序。一切都设置好了，但是当代码到达模拟器中的以下行时，它会显示“应用程序已意外停止”并且日志 cat 显示 NullPointerException。我也给了我发现的尽可能多的权限。请帮助我在清单文件中必须赋予哪些特定权限以及如何解决问题。

startActivity(Intent.createChooser(send, "This is the chooser title"));

发送是我的意图。

完整的日志猫消息如下：

11-01 23:21:37.721: W/IInputConnectionWrapper(442): showStatusIcon on inactive InputConnection
11-01 23:21:39.781: I/msg(442): this is offhook
11-01 23:21:43.991: I/msg(442): this is idle
11-01 23:21:43.991: I/msgfinal(442): this is it
11-01 23:21:43.991: I/msg(442): this is from msg
11-01 23:21:43.991: I/sha(442): here
11-01 23:21:43.991: D/AndroidRuntime(442): Shutting down VM
11-01 23:21:43.991: W/dalvikvm(442): threadid=1: thread exiting with uncaught exception (group=0x40015560)
11-01 23:21:43.991: E/AndroidRuntime(442): FATAL EXCEPTION: main
11-01 23:21:43.991: E/AndroidRuntime(442): java.lang.NullPointerException
11-01 23:21:43.991: E/AndroidRuntime(442):  at android.app.Activity.startActivityForResult(Activity.java:2827)
11-01 23:21:43.991: E/AndroidRuntime(442):  at android.app.Activity.startActivity(Activity.java:2933)
11-01 23:21:43.991: E/AndroidRuntime(442):  at com.example.dialing.MainActivity.fun(MainActivity.java:33)
11-01 23:21:43.991: E/AndroidRuntime(442):  at com.example.dialing.PhoneCallListener.onCallStateChanged(MainActivity.java:104)
11-01 23:21:43.991: E/AndroidRuntime(442):  at android.telephony.PhoneStateListener$2.handleMessage(PhoneStateListener.java:319)
11-01 23:21:43.991: E/AndroidRuntime(442):  at android.os.Handler.dispatchMessage(Handler.java:99)
11-01 23:21:43.991: E/AndroidRuntime(442):  at android.os.Looper.loop(Looper.java:123)
11-01 23:21:43.991: E/AndroidRuntime(442):  at android.app.ActivityThread.main(ActivityThread.java:3683)
11-01 23:21:43.991: E/AndroidRuntime(442):  at java.lang.reflect.Method.invokeNative(Native Method)
11-01 23:21:43.991: E/AndroidRuntime(442):  at java.lang.reflect.Method.invoke(Method.java:507)
11-01 23:21:43.991: E/AndroidRuntime(442):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
11-01 23:21:43.991: E/AndroidRuntime(442):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
11-01 23:21:43.991: E/AndroidRuntime(442):  at dalvik.system.NativeStart.main(Native Method)
11-01 23:21:48.481: I/Process(442): Sending signal. PID: 442 SIG: 9

请注意，直到“这里”（第 6 行），它是日志。I 用于检查，它是startActivity函数之前的行。

        Intent msg=new Intent(Intent.ACTION_SEND);
        String[] recipients={"myid@gmail.com"};

        msg.putExtra(Intent.EXTRA_EMAIL, recipients);

        msg.putExtra(Intent.EXTRA_TEXT, "This is the email body");
        msg.putExtra(Intent.EXTRA_SUBJECT, "This is the email subject");

        //msg.setType("message/rfc822");
        msg.setType("*/*");

        //context.startActivity(Intent.createChooser(msg, "This is the chooser title"));
        Log.i("msg","this is from msg");

        //calling into main activity
        MainActivity ma=new MainActivity();
        ma.fun(msg);

//这个函数在mainActivity里面

public void fun(Intent send)
{
    Log.i("sha","here");
    startActivity(Intent.createChooser(send, "This is the chooser title"));

    Log.i("sha","here2");
}
4

4 回答 4

5

走这条路：

Intent email = new Intent(Intent.ACTION_SEND);
    email.putExtra(Intent.EXTRA_EMAIL,new String[] { "rahul@mail.com"});
    email.putExtra(Intent.EXTRA_SUBJECT,"Contact Us");
    email.putExtra(Intent.EXTRA_TEXT,"sent a message using the contact us ");

    email.setType("message/rfc822");

    startActivityForResult(Intent.createChooser(email, "Choose an Email client:"),
                        1);

然后创建方法onActivityResult

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {

    if(requestCode == MY_REQUEST_CODE) {
        if(resultCode == RESULT_OK) {


        } else {

            Intent ingoHome = new Intent(abc.this,
                    pqr.class);
            ingoHome.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
            startActivity(ingoHome);


        }
    }

    finish();

}
于 2012-11-02T04:14:28.517 回答
1

试试这个 。. . . . 它工作正常。 

Intent emailIntent = new Intent(android.content.Intent.ACTION_SEND); 
emailIntent.putExtra(android.content.Intent.EXTRA_EMAIL, new String[]{""}); 
emailIntent.putExtra(android.content.Intent.EXTRA_SUBJECT,""); 
emailIntent.putExtra(android.content.Intent.EXTRA_TEXT,""); 
startActivity(Intent.createChooser(emailIntent, "Send mail..."));

如果您需要在电子邮件中附加任何其他文件，您可以将其添加到“emailIntent.putExtra();”中

于 2012-11-02T03:53:52.270 回答
0

问题是您使用的上下文。代码很好。只是不使用

MainActivity ma=new MainActivity();
ma.fun(msg);

像使用它一样

MainActivity.this.fun(msg);
于 2012-11-02T04:27:55.783 回答
0

java.lang.NullPointerException基本上意味着您正在引用一个不存在的对象（尚不存在。）

尝试注释掉或删除这些行：

MainActivity ma=new MainActivity();
ma.fun(msg);

并用您的 MainActivity.fun(Intent msg) 方法中的代码替换它们，匹配变量名称：

Log.i("sha","here");
startActivity(Intent.createChooser(msg, "This is the chooser title"));
Log.i("sha","here2");

如果我正确阅读了您的代码，则您一直在尝试创建 current 的另一个实例Activity并将其传递给Intent包含Context您 current 的Activity. 您已经在一个实例中MainActivity（它是由 Android 为您实例化的。）

编辑： startActivity 和 startActivityforResult 都启动另一个活动， startActivityforResult 期望结果返回到第一个活动中的回调。我会努力让 startActivity 首先工作，如果需要，您可以随时将其转换为 startActivityforResult。

由于您的应用程序在 崩溃MainActivity.fun(MainActivity.java:33)，因此 startActivity 似乎在实例化之前正在接收“发送”。

我只是要回应其他所有人，并说你的代码应该可以工作..只要你巨大的上下文代码块是调用你的 fun() 方法的唯一地方。如果你把它全部放在它自己的方法中，它会是什么样子：

class MainActivity extends Activity {
    private static final String TAG = Controller.class.getSimpleName();

    /* fields, other methods */

    private void sendMail(){
        Intent msg=new Intent(Intent.ACTION_SEND);
        String[] recipients={"myid@gmail.com"};
        msg.putExtra(Intent.EXTRA_EMAIL, recipients);
        msg.putExtra(Intent.EXTRA_TEXT, "This is the email body");
        msg.putExtra(Intent.EXTRA_SUBJECT, "This is the email subject");
        // I personally use application/octet-stream because it
        // shows all my email clients, but not much other useless stuff.
        // Might get me flamed, though lol :)
        msg.setType("application/octet-stream");
        MainActivity.this.getApplicationContext().startActivity(
            Intent.createChooser(msg, "This is the chooser title")
        );
        Log.i(TAG,"made it! :D");
    }/*end sendMail()*/

    /* more fields and methods */

}/*end MainActivity*/
于 2012-11-02T04:55:37.143 回答