如何在android中處理onClickListener？

Question

我想寫一個簡單的android應用程序來幫助解釋一些實驗室結果。

 
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); 

    } 

} 

它編譯和運行，但當我按「解釋」按鈕時，它只是說應用程序...意外停止。請再試一次。 （強制關閉）。

我完全陌生於android編程...所以我想這會是我犯的一些非常愚蠢的錯誤，但請大家幫忙。謝謝。

更新：將代碼更改爲此（減去邏輯部分，而我將在稍後完成） 但按下按鈕時仍然掛起。

 
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，你要投這類型來看，這是

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

其次，你打電話這來自onclickListener。所以findViewById（）真的不應該編譯。您需要

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

而且也是在Java中，類應與資本lettors開始，所以它應該是

public class Pinit extends Activity{

更新：

findViewById（R.id。 InpPH）解析爲 EditTex

不，不。它解析爲一個View。在視圖上調用.toString（）不是你想要的。你想幹什麼

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

Answer 2

我想你在這樣的呼叫一送NumberFormatException：

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

至於文檔，如果字符串是空的NumberFormatException是得了具有長度爲零或者不能被解析爲浮點值。

但是，檢查logCat跟蹤會得到一個乾淨的答案。