java - 尝试制作带有对话的程序，启动时崩溃

Question

看来是对话框里面的按钮出了问题，不知道怎么解决

我有一项任务是制作一个程序，该程序从对话中的 EditText 中捕获值，然后将它们用于一个简单的方程式...我必须说我是 android 编程的新手，因此了解不多，但程序当我运行它时一直崩溃，我不知道为什么而且我自己无法检测到任何问题，我将添加代码，如果有人可以检测到任何(或许多)问题请指出，谢谢。

public class MainActivity extends Activity {
Dialog d1;
Integer r1, r2, vol, vot;
EditText ed1;
TextView txt1, txt2, txt3, txt4;



@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Button btn1= (Button) findViewById(R.id.button1);
    Button btn3= (Button) findViewById(R.id.button3);
    Button btn4= (Button) findViewById(R.id.button4);
    Button btn5= (Button) findViewById(R.id.button5);
    final TextView txt1= (TextView) findViewById(R.id.textView1);
    final TextView txt2= (TextView) findViewById(R.id.textView2);
    final TextView txt3= (TextView) findViewById(R.id.textView3);
    final TextView txt4=(TextView) findViewById(R.id.textView4);
    final int r1= Integer.valueOf(1000);
    final int r2=Integer.valueOf(1000);
    final int vol=Integer.valueOf(10);




btn1.setOnClickListener(new OnClickListener(){
    @Override
    public void onClick(View arg0) {
        final Dialog d1 = new Dialog(MainActivity.this);
        d1.setContentView(R.layout.valor);
        d1.setTitle("Valor de R1");
        final EditText ed1 = (EditText) findViewById(R.id.editText1);
        d1.show();
        Button btn2 = (Button) findViewById(R.id.button2);
        btn2.setOnClickListener(new OnClickListener(){
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                int r1=Integer.parseInt(ed1.getText().toString());
                txt1.setText(String.valueOf(r1));}
                catch(NumberFormatException nfe)
                {
                    nfe.printStackTrace();
                }
                txt1.setText(String.valueOf(r1));
                d1.dismiss();
            };
        });
    }
});
**NOTE: THIS SAME SEQUENCE IS REPEATED TWICE MORE FOR THE 2 OTHER VARIABLES **

btn5.setOnClickListener(new OnClickListener(){
    @Override
    public void onClick(View arg0) {
        // TODO Auto-generated method stub
        vot=(r2/(r1+r2))*vol;
        txt4.setText("Resultado: " +String.valueOf(vot));
    };
});}

日志:

03-12 21:06:12.781: E/ViewRootImpl(29660): sendUserActionEvent() mView == null
03-12 21:06:17.966: D/AndroidRuntime(29660): Shutting down VM
03-12 21:06:17.966: W/dalvikvm(29660): threadid=1: thread exiting with uncaught exception (group=0x41d11700)
03-12 21:06:17.971: E/AndroidRuntime(29660): FATAL EXCEPTION: main
03-12 21:06:17.971: E/AndroidRuntime(29660): java.lang.NullPointerException
03-12 21:06:17.971: E/AndroidRuntime(29660):    at com.uia.examenno1.MainActivity$1.onClick(MainActivity.java:49)
03-12 21:06:17.971: E/AndroidRuntime(29660):    at android.view.View.performClick(View.java:4489)
03-12 21:06:17.971: E/AndroidRuntime(29660):    at android.view.View$PerformClick.run(View.java:18803)
03-12 21:06:17.971: E/AndroidRuntime(29660):    at android.os.Handler.handleCallback(Handler.java:730)
03-12 21:06:17.971: E/AndroidRuntime(29660):    at android.os.Handler.dispatchMessage(Handler.java:92)
03-12 21:06:17.971: E/AndroidRuntime(29660):    at android.os.Looper.loop(Looper.java:137)
03-12 21:06:17.971: E/AndroidRuntime(29660):    at android.app.ActivityThread.main(ActivityThread.java:5493)
03-12 21:06:17.971: E/AndroidRuntime(29660):    at java.lang.reflect.Method.invokeNative(Native Method)
03-12 21:06:17.971: E/AndroidRuntime(29660):    at java.lang.reflect.Method.invoke(Method.java:525)
03-12 21:06:17.971: E/AndroidRuntime(29660):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1209)
03-12 21:06:17.971: E/AndroidRuntime(29660):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1025)
03-12 21:06:17.971: E/AndroidRuntime(29660):    at dalvik.system.NativeStart.main(Native Method)

Answer 1

由于您没有处理任何异常，它无论如何都会崩溃，因为 txt1.toString() 可能不会被解析为整数。您应该改用 txt1.getText().toString()。如果这没有引起问题，请附上您的日志，您可以考虑阅读重构书籍:

try {
    Integer.parseInt(txt1.getText().toString());
} catch (NumberFormatException nfe) {
    nfe.printStackTrace();
}