android，尝试打开某个 Activity 时应用程序崩溃

Question

我在尝试开发的应用程序上输入一个 Activity/屏幕时遇到问题。似乎每次我按下按钮打开该 Activity 时，应用程序都会崩溃。这是java文件:

public class login extends Activity{

// all kinds of functions //


protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.login);


    place();

    btn_clr.setOnClickListener(new View.OnClickListener() {
        public void onClick(View view) {
            clearForm();
        }
        });

    btn_back.setOnClickListener(new View.OnClickListener() {
        public void onClick(View view) {
            Intent myIntent = new Intent(view.getContext(), MainActivity.class);
            startActivityForResult(myIntent, 0);
            finish();
        }
        });

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.login, menu);
    return true;
}

这是layout.xml 文件:

< RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".login.java"
android:orientation="vertical" >

// setting all the buttons and texts //

< /RelativeLayout>

这是 menu.xml 文件

< menu xmlns:android="http://schemas.android.com/apk/res/android" >
< item

    android:id="@+id/menu_settings"
    android:orderInCategory="100"
    android:showAsAction="never"
    android:title="@string/log_str"/>

< /menu>

这是对 Activity 的调用:

    btn_log.setOnClickListener(new View.OnClickListener() {
        public void onClick(View view) {
            Intent myIntent = new Intent(view.getContext(), login.class);
            startActivityForResult(myIntent, 0);
            finish();
        }
        });

郁闷了我两天。预先感谢您

Answer 1

在这种情况下，理想的做法是尝试通过调试器查找错误。您可以使用的一个技巧是在每个异常上设置一个断点...这样，一旦抛出异常，它就会中断，您将能够检查错误和错误点的堆栈跟踪.

这个答案中对此进行了描述(讽刺的是，针对我不久前问过的一个问题:)):https://stackoverflow.com/a/6342519/5416

In Eclipse, switch to the "debug" perspective. In the "Breakpoint" view, you will notice a little icon (at the top right, near the "minimize" button of the view) with a J and an exclamation point. This is the trigger to add "exception" breakpoints.

With this dialog, you can tell the debugger to suspend and caught and uncaught exceptions alike.