Question

因此，我的应用程序从文本视图中读取数据，然后将其保存到文件中。无论如何，当我按下提交按钮时，它会崩溃。我不知道，为什么，我试图删除粗略的代码，但这也不起作用。

无论如何，如果你能看看我的代码，看看我做错了什么，那就太好了;如果有人知道如何复制LogCat，那将是非常酷的。

我的代码：

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.login);
    send = (Button) findViewById(R.id.bLogIn);
    user = (EditText) findViewById(R.id.eTuser);
    pass = (EditText) findViewById(R.id.eTpassword);
    staySignedIn = (CheckBox) findViewById(R.id.Cbstay);
    send.setOnClickListener(this);
    try {
        Fos = openFileOutput(FILENAME, Context.MODE_PRIVATE);
        Fos.close();
    } catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    if (staySignedIn.isChecked()) {

        String u = user.getText().toString();
        String p = pass.getText().toString();
        File f = new File(FILENAME);
        try {
            Fos = new FileOutputStream(f);
            //Write some Data
            Fos.close();
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } 


    } 

}

public void onClick(View v) {
    // TODO Auto-generated method stub
    switch (v.getId()) {
    case R.id.bLogIn:
        if (pass.length() == 0)
            Toast.makeText(this,
                    "Try to type in your username and password again!",
                    Toast.LENGTH_LONG).show();
        else if (user.length() == 0)
            Toast.makeText(this,
                    "Try to type in your username and password again!",
                    Toast.LENGTH_LONG).show();
        else {

            String u = user.getText().toString();
            String p = pass.getText().toString();
            Bundle send = new Bundle();
            send.putString("key", u);
            send.putString("key", p);
            Intent a = new Intent(LogIn.this, logincheck.class);
            startActivity(a);
            Toast.makeText(this, "Were signing you in!", Toast.LENGTH_LONG)
                    .show();
            break;
        }
    }

}

}

Logcat：

 01-19 07:02:42.341: W/System.err(3074): java.io.FileNotFoundException: /userandpass (Read-only file system)
    01-19 07:02:42.341: W/System.err(3074):         at   org.apache.harmony.luni.platform.OSFileSystem.openImpl(Native Method)
    01-19 07:02:42.341: W/System.err(3074):         at   org.apache.harmony.luni.platform.OSFileSystem.open(OSFileSystem.java:152)
    01-19 07:02:42.341: W/System.err(3074):         at java.io.FileOutputStream.<init>(FileOutputStream.java:97)
    01-19 07:02:42.341: W/System.err(3074):         at java.io.FileOutputStream.<init>(FileOutputStream.java:69)
    01-19 07:02:42.341: W/System.err(3074):         at com.gta5news.bananaphone.LogIn.onCreate(LogIn.java:59)
    01-19 07:02:42.341: W/System.err(3074):         at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
01-19 07:02:42.341: W/System.err(3074):         at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
01-19 07:02:42.341: W/System.err(3074):         at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
01-19 07:02:42.341: W/System.err(3074):         at android.app.ActivityThread.access$2300(ActivityThread.java:125)
01-19 07:02:42.351: W/System.err(3074):         at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
01-19 07:02:42.351: W/System.err(3074):         at android.os.Handler.dispatchMessage(Handler.java:99)
01-19 07:02:42.351: W/System.err(3074):         at android.os.Looper.loop(Looper.java:123)
01-19 07:02:42.351: W/System.err(3074):         at android.app.ActivityThread.main(ActivityThread.java:4627)
01-19 07:02:42.351: W/System.err(3074):         at java.lang.reflect.Method.invokeNative(Native Method)
01-19 07:02:42.351: W/System.err(3074):         at java.lang.reflect.Method.invoke(Method.java:521)
01-19 07:02:42.351: W/System.err(3074):         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
01-19 07:02:42.351: W/System.err(3074):         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
01-19 07:02:42.351: W/System.err(3074):         at dalvik.system.NativeStart.main(Native Method)
01-19 07:02:47.371: W/KeyCharacterMap(3074): No keyboard for id 0
01-19 07:02:47.371: W/KeyCharacterMap(3074): Using default keymap: /system/usr/keychars/qwerty.kcm.bin
01-19 07:02:49.421: D/AndroidRuntime(3074): Shutting down VM
01-19 07:02:49.421: W/dalvikvm(3074): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
01-19 07:02:49.421: E/AndroidRuntime(3074): FATAL EXCEPTION: main
01-19 07:02:49.421: E/AndroidRuntime(3074): android.content.ActivityNotFoundException: Unable to find explicit activity class {com.gta5news.bananaphone/com.gta5news.bananaphone.logincheck}; have you declared this activity in your AndroidManifest.xml?
01-19 07:02:49.421: E/AndroidRuntime(3074):     at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1404)
01-19 07:02:49.421: E/AndroidRuntime(3074):     at android.app.Instrumentation.execStartActivity(Instrumentation.java:1378)
01-19 07:02:49.421: E/AndroidRuntime(3074):     at android.app.Activity.startActivityForResult(Activity.java:2817)
01-19 07:02:49.421: E/AndroidRuntime(3074):     at android.app.Activity.startActivity(Activity.java:2923)
01-19 07:02:49.421: E/AndroidRuntime(3074):     at com.gta5news.bananaphone.LogIn.onClick(LogIn.java:95)
01-19 07:02:49.421: E/AndroidRuntime(3074):     at android.view.View.performClick(View.java:2408)
01-19 07:02:49.421: E/AndroidRuntime(3074):     at android.view.View$PerformClick.run(View.java:8816)
01-19 07:02:49.421: E/AndroidRuntime(3074):     at android.os.Handler.handleCallback(Handler.java:587)
01-19 07:02:49.421: E/AndroidRuntime(3074):     at android.os.Handler.dispatchMessage(Handler.java:92)
01-19 07:02:49.421: E/AndroidRuntime(3074):     at android.os.Looper.loop(Looper.java:123)
01-19 07:02:49.421: E/AndroidRuntime(3074):     at android.app.ActivityThread.main(ActivityThread.java:4627)
01-19 07:02:49.421: E/AndroidRuntime(3074):     at java.lang.reflect.Method.invokeNative(Native Method)
01-19 07:02:49.421: E/AndroidRuntime(3074):     at java.lang.reflect.Method.invoke(Method.java:521)
01-19 07:02:49.421: E/AndroidRuntime(3074):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
01-19 07:02:49.421: E/AndroidRuntime(3074):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
01-19 07:02:49.421: E/AndroidRuntime(3074):     at dalvik.system.NativeStart.main(Native Method)

Answer 1

如果您查看日志，答案就在其中。检查一下

E/AndroidRuntime(3074): android.content.ActivityNotFoundException: Unable to find explicit activity class {com.gta5news.bananaphone/com.gta5news.bananaphone.logincheck}; have you declared this activity in your AndroidManifest.xml?

它表示您没有声明您尝试在清单中单击按钮时打开的新活动。将它添加到您的清单中它应该可以正常工作。

它正试图在清单中找到您的logincheck类。

作为旁注，请尝试遵循java惯例。使用驼峰套管来获得类名等。例如，您的类应该是LoginCheck的名称。有关java约定的更多信息here。

您的清单应该已有活动代码。在它下添加你的新活动

<activity name="com.gta5news.bananaphone.logincheck" />

应该这样做。

Answer 2

main 01-19 07:02:49.421: E/AndroidRuntime(3074): android.content.ActivityNotFoundException: Unable to find explicit activity class

表示您尚未在logincheck文件中声明AndroidManifest.xml个活动。

像这样添加：

    <activity android:name=".logincheck" android:label="@string/app_name"></activity>

android:name就像你给了你的其他活动一样..

单击按钮时应用程序崩溃

2 个答案: