Android - 不幸的是，myapp已经停止

Question

我正在学习开发Android应用程序，并且遇到了与我的应用程序有关的问题。我创建了一个应用程序，允许用户输入一些文本，当按下按钮时，会调用一个函数，将输入字符串解析为double，然后显示它。我没有收到任何错误，但是每当我在任何模拟器上运行应用程序时，它都会显示“不幸的是，myapp已停止”。

这里是logcat的：

04-04 14:34:11.579: I/dalvikvm(657): Wrote stack traces to '/data/anr/traces.txt' 
04-04 14:34:11.969: I/dalvikvm(657): threadid=3: reacting to signal 3 
04-04 14:34:12.089: I/dalvikvm(657): Wrote stack traces to '/data/anr/traces.txt' 
04-04 14:34:12.720: I/dalvikvm(657): threadid=3: reacting to signal 3 
04-04 14:34:12.860: I/dalvikvm(657): Wrote stack traces to '/data/anr/traces.txt' 
04-04 14:34:12.979: I/dalvikvm(657): threadid=3: reacting to signal 3 
04-04 14:34:13.069: I/dalvikvm(657): Wrote stack traces to '/data/anr/traces.txt' 
04-04 14:34:13.479: I/dalvikvm(657): threadid=3: reacting to signal 3 
04-04 14:34:13.599: I/dalvikvm(657): Wrote stack traces to '/data/anr/traces.txt' 
04-04 14:34:14.009: I/dalvikvm(657): threadid=3: reacting to signal 3 
04-04 14:34:14.129: I/dalvikvm(657): Wrote stack traces to '/data/anr/traces.txt' 
04-04 14:34:14.320: D/libEGL(657): loaded /system/lib/egl/libGLES_android.so 
04-04 14:34:14.390: D/libEGL(657): loaded /system/lib/egl/libEGL_emulation.so 
04-04 14:34:14.409: D/(657): HostConnection::get() New Host Connection established 0xd7820, tid 657 
04-04 14:34:14.429: D/libEGL(657): loaded /system/lib/egl/libGLESv1_CM_emulation.so 
04-04 14:34:14.449: D/libEGL(657): loaded /system/lib/egl/libGLESv2_emulation.so 
04-04 14:34:14.519: I/dalvikvm(657): threadid=3: reacting to signal 3 
04-04 14:34:14.579: I/dalvikvm(657): Wrote stack traces to '/data/anr/traces.txt' 
04-04 14:34:14.719: W/EGL_emulation(657): eglSurfaceAttrib not implemented 
04-04 14:34:14.769: D/OpenGLRenderer(657): Enabling debug mode 0 
04-04 14:34:15.049: I/dalvikvm(657): threadid=3: reacting to signal 3 
04-04 14:34:15.173: I/dalvikvm(657): Wrote stack traces to '/data/anr/traces.txt' 
04-04 14:34:15.579: I/dalvikvm(657): threadid=3: reacting to signal 3 
04-04 14:34:15.790: I/dalvikvm(657): Wrote stack traces to '/data/anr/traces.txt' 
04-04 14:34:16.030: I/dalvikvm(657): threadid=3: reacting to signal 3 
04-04 14:34:16.109: I/dalvikvm(657): Wrote stack traces to '/data/anr/traces.txt' 
04-04 14:34:16.549: I/dalvikvm(657): threadid=3: reacting to signal 3 
04-04 14:34:16.739: I/dalvikvm(657): Wrote stack traces to '/data/anr/traces.txt' 
04-04 14:34:17.029: I/dalvikvm(657): threadid=3: reacting to signal 3 
04-04 14:34:17.220: I/dalvikvm(657): Wrote stack traces to '/data/anr/traces.txt' 
04-04 14:34:27.099: D/AndroidRuntime(657): Shutting down VM 
04-04 14:34:27.099: W/dalvikvm(657): threadid=1: thread exiting with uncaught exception (group=0x409c01f8) 
04-04 14:34:27.219: E/AndroidRuntime(657): FATAL EXCEPTION: main 
04-04 14:34:27.219: E/AndroidRuntime(657): java.lang.IllegalStateException: Could not execute method of the activity 
04-04 14:34:27.219: E/AndroidRuntime(657): at android.view.View$1.onClick(View.java:3044) 
04-04 14:34:27.219: E/AndroidRuntime(657): at android.view.View.performClick(View.java:3511) 
04-04 14:34:27.219: E/AndroidRuntime(657): at android.view.View$PerformClick.run(View.java:14105) 
04-04 14:34:27.219: E/AndroidRuntime(657): at android.os.Handler.handleCallback(Handler.java:605) 
04-04 14:34:27.219: E/AndroidRuntime(657): at android.os.Handler.dispatchMessage(Handler.java:92) 
04-04 14:34:27.219: E/AndroidRuntime(657): at android.os.Looper.loop(Looper.java:137) 
04-04 14:34:27.219: E/AndroidRuntime(657): at android.app.ActivityThread.main(ActivityThread.java:4424) 
04-04 14:34:27.219: E/AndroidRuntime(657): at java.lang.reflect.Method.invokeNative(Native Method) 
04-04 14:34:27.219: E/AndroidRuntime(657): at java.lang.reflect.Method.invoke(Method.java:511) 
04-04 14:34:27.219: E/AndroidRuntime(657): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 
04-04 14:34:27.219: E/AndroidRuntime(657): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 
04-04 14:34:27.219: E/AndroidRuntime(657): at dalvik.system.NativeStart.main(Native Method) 
04-04 14:34:27.219: E/AndroidRuntime(657): Caused by: java.lang.reflect.InvocationTargetException 
04-04 14:34:27.219: E/AndroidRuntime(657): at java.lang.reflect.Method.invokeNative(Native Method) 
04-04 14:34:27.219: E/AndroidRuntime(657): at java.lang.reflect.Method.invoke(Method.java:511) 
04-04 14:34:27.219: E/AndroidRuntime(657): at android.view.View$1.onClick(View.java:3039) 
04-04 14:34:27.219: E/AndroidRuntime(657): ... 11 more 
04-04 14:34:27.219: E/AndroidRuntime(657): Caused by: java.lang.NumberFormatException: Invalid double: "android.widget.EditText@40f7be40" 
04-04 14:34:27.219: E/AndroidRuntime(657): at java.lang.StringToReal.invalidReal(StringToReal.java:63) 
04-04 14:34:27.219: E/AndroidRuntime(657): at java.lang.StringToReal.initialParse(StringToReal.java:114) 
04-04 14:34:27.219: E/AndroidRuntime(657): at java.lang.StringToReal.parseDouble(StringToReal.java:263) 
04-04 14:34:27.219: E/AndroidRuntime(657): at java.lang.Double.parseDouble(Double.java:295) 
04-04 14:34:27.219: E/AndroidRuntime(657): at com.example.coinage.MainActivity.convert(MainActivity.java:25) 
04-04 14:34:27.219: E/AndroidRuntime(657): ... 14 more 
04-04 14:34:28.069: I/dalvikvm(657): threadid=3: reacting to signal 3 
04-04 14:34:28.179: I/dalvikvm(657): Wrote stack traces to '/data/anr/traces.txt' 
04-04 14:34:29.729: I/Process(657): Sending signal. PID: 657 SIG: 9 

方法进行计算

public void convert(View view){ 
    int countOf2Po = 0, countOf1Po = 0, countOf50p = 0, countOf20p = 0, countOf2p = 0, countOf1p = 0; 
    EditText amt = (EditText) findViewById (R.id.amount); 
    TextView penny = (TextView) findViewById (R.id.penny); 
    double amount = Double.parseDouble(amt.toString()) * 100; 
    while(amount >= 200){ 
     amount = amount - 200; 
     countOf2Po++; 
    } 
    while(amount >= 100){ 
     amount = amount - 100; 
     countOf1Po++; 
    } 
    while(amount >= 50){ 
     amount = amount - 50; 
     countOf50p++; 
    } 
    while(amount >= 20){ 
      amount = amount - 20; 
      countOf20p++; 
    } 
    while(amount >= 2){ 
     amount = amount - 2; 
     countOf2p++; 
    } 
    if(amount % 2 != 0){ 
     countOf1p++; 
    } 
    penny.setText("Converting " + penny + " into coins."); 
    penny.setVisibility(View.VISIBLE); 
} 

Answer 1

你试图将EditText的toString()值转换为双，这是不文本输入EditText就像您期望的那样，但名称是与实例的哈希码连接的类的名称：

Object类的toString方法返回由 其中物体是一个实例，所述-SIGN 字符'@”的类的名称的字符串，并且散列 的无符号十六进制表示法对象的代码。换句话说，该方法返回一个字符串等于 ，它的值：

getClass().getName() + '@' + Integer.toHexString(hashCode()) 

你想要做什么，是使用getText()检索输入的文本，并且将其转换成一个String：

double amount = Double.parseDouble(amt.getText().toString()) * 100; 

请注意，如果输入不是适当的双倍，这可能会导致NumberFormatException。