如何在android中处理onClickListener？

Question

我想写一个简单的android应用程序来帮助解释一些实验室结果。

 
package org.android.bloodgas; 

import android.app.Activity; 
import android.os.Bundle; 
import android.view.View; 
import android.widget.TextView; 
import android.widget.Button; 

public class pinit extends Activity { 


    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.main); 

     Button interpretButton = (Button) findViewById(R.id.Interpret); 

     //interpretButton.setOnClickListener(this); 
     View.OnClickListener myhandler = new View.OnClickListener() { 
      @Override 
      public void onClick(View v) { 
        float inpPH, inpPO2, inpPCO2, inpHCO3, inpBE; 
        inpPH = Float.valueOf(findViewById(R.id.InpPH).toString()).floatValue(); 
        inpPO2 = Float.valueOf(findViewById(R.id.InpO2).toString()).floatValue(); 
        inpPCO2 = Float.valueOf(findViewById(R.id.InpCO2).toString()).floatValue(); 
        inpHCO3 = Float.valueOf(findViewById(R.id.InpHCO3).toString()).floatValue(); 
        inpBE = Float.valueOf(findViewById(R.id.InpBE).toString()).floatValue(); 

        TextView interpretation; 
        interpretation = (TextView) findViewById(R.id.Interpretation); 

        String sResult = null; 
        if (inpPH < 7.35) { 
         // Acidosis 
         sResult.concat("Acidosis. "); 
        } else { 
         if (inpPH > 7.45) { 
          // Alkalosis 
          sResult.concat("Alkalosis. "); 
         } else { 
          // Normal acidity, 7.35-7.45 
          sResult.concat("Normal pH. "); 
         } 
        } 
        interpretation.setText(sResult); 
      } 
     }; 

     interpretButton.setOnClickListener(myhandler); 

    } 

} 

它编译和运行，但当我按“解释”按钮时，它只是说应用程序...意外停止。请再试一次。 （强制关闭）。

我完全陌生于android编程...所以我想这会是我犯的一些非常愚蠢的错误，但请大家帮忙。谢谢。

更新：将代码更改为此（减去逻辑部分，而我将在稍后完成） 但按下按钮时仍然挂起。

 
package org.android.bloodgas; 

import android.app.Activity; 
import android.os.Bundle; 
import android.view.View; 
import android.widget.EditText; 
import android.widget.Button; 

public class Pinit extends Activity { 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.main); 

     Button interpretButton = (Button) findViewById(R.id.Interpret); 

     View.OnClickListener myhandler = new View.OnClickListener() { 
      @Override 
      public void onClick(View v) { 
        float inpPH, inpPO2, inpPCO2, inpHCO3, inpBE; 
        inpPH = Float.valueOf(((EditText) Pinit.this.findViewById(R.id.InpPH)).toString()).floatValue(); 
        inpPO2 = Float.valueOf(((EditText) Pinit.this.findViewById(R.id.InpO2)).toString()).floatValue(); 
        inpPCO2 = Float.valueOf(((EditText) Pinit.this.findViewById(R.id.InpCO2)).toString()).floatValue(); 
        inpHCO3 = Float.valueOf(((EditText) Pinit.this.findViewById(R.id.InpHCO3)).toString()).floatValue(); 
        inpBE = Float.valueOf(((EditText) Pinit.this.findViewById(R.id.InpBE)).toString()).floatValue(); 
        // ... 
      } 
     }; 

     interpretButton.setOnClickListener(myhandler); 

    } 

} 

的logcat：

 
12-07 03:37:02.231: WARN/dalvikvm(1074): threadid=1: thread exiting with uncaught exception (group=0x4001d800) 
12-07 03:37:02.332: ERROR/AndroidRuntime(1074): FATAL EXCEPTION: main 
12-07 03:37:02.332: ERROR/AndroidRuntime(1074): java.lang.NumberFormatException: android.widget.EditText@44f47e60 
12-07 03:37:02.332: ERROR/AndroidRuntime(1074):  at org.apache.harmony.luni.util.FloatingPointParser.initialParse(FloatingPointParser.java:130) 
12-07 03:37:02.332: ERROR/AndroidRuntime(1074):  at org.apache.harmony.luni.util.FloatingPointParser.parseFloat(FloatingPointParser.java:319) 
12-07 03:37:02.332: ERROR/AndroidRuntime(1074):  at java.lang.Float.parseFloat(Float.java:291) 
12-07 03:37:02.332: ERROR/AndroidRuntime(1074):  at java.lang.Float.valueOf(Float.java:330) 
12-07 03:37:02.332: ERROR/AndroidRuntime(1074):  at org.android.bloodgas.Pinit$1.onClick(Pinit.java:22) 
12-07 03:37:02.332: ERROR/AndroidRuntime(1074):  at android.view.View.performClick(View.java:2408) 
12-07 03:37:02.332: ERROR/AndroidRuntime(1074):  at android.view.View$PerformClick.run(View.java:8816) 
12-07 03:37:02.332: ERROR/AndroidRuntime(1074):  at android.os.Handler.handleCallback(Handler.java:587) 
12-07 03:37:02.332: ERROR/AndroidRuntime(1074):  at android.os.Handler.dispatchMessage(Handler.java:92) 
12-07 03:37:02.332: ERROR/AndroidRuntime(1074):  at android.os.Looper.loop(Looper.java:123) 
12-07 03:37:02.332: ERROR/AndroidRuntime(1074):  at android.app.ActivityThread.main(ActivityThread.java:4627) 
12-07 03:37:02.332: ERROR/AndroidRuntime(1074):  at java.lang.reflect.Method.invokeNative(Native Method) 
12-07 03:37:02.332: ERROR/AndroidRuntime(1074):  at java.lang.reflect.Method.invoke(Method.java:521) 
12-07 03:37:02.332: ERROR/AndroidRuntime(1074):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 
12-07 03:37:02.332: ERROR/AndroidRuntime(1074):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 
12-07 03:37:02.332: ERROR/AndroidRuntime(1074):  at dalvik.system.NativeStart.main(Native Method) 
12-07 03:37:02.382: WARN/ActivityManager(68): Force finishing activity org.android.bloodgas/.Pinit 
12-07 03:37:02.952: WARN/ActivityManager(68): Activity pause timeout for HistoryRecord{44fbfc90 org.android.bloodgas/.Pinit} 
12-07 03:37:07.761: INFO/Process(1074): Sending signal. PID: 1074 SIG: 9 
12-07 03:37:09.852: INFO/ActivityManager(68): Process org.android.bloodgas (pid 1074) has died. 
12-07 03:37:09.862: INFO/WindowManager(68): WIN DEATH: Window{44fa71e0 org.android.bloodgas/org.android.bloodgas.Pinit paused=false} 
12-07 03:37:15.931: WARN/ActivityManager(68): Activity destroy timeout for HistoryRecord{44fbfc90 org.android.bloodgas/.Pinit} 

Answer 1

我首先看到的是，你要投这类型来看，这是

inpPH = Float.valueOf(findViewById(R.id.InpPH).toString()).floatValue();

其次，你打电话这来自onclickListener。所以findViewById（）真的不应该编译。您需要

inpPH = Float.valueOf((TypeOfView) pinit.this.findViewById(R.id.InpPH).toString()).floatValue(); 

而且也是在Java中，类应与资本lettors开始，所以它应该是

public class Pinit extends Activity{

更新：

findViewById（R.id。 InpPH）解析为 EditTex

不，不。它解析为一个View。在视图上调用.toString（）不是你想要的。你想干什么

((EditText) pinit.this.findViewById(R.id.InpPH)).getText().toString() 

Answer 2

我想你在这样的呼叫一送NumberFormatException：

Float.valueOf(findViewById(R.id.InpPH).toString()) 

至于文档，如果字符串是空的NumberFormatException是得了具有长度为零或者不能被解析为浮点值。

但是，检查logCat跟踪会得到一个干净的答案。