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前幾天我問這個問題，但我只是意識到，我包括了錯誤的logcat的錯誤，這已經包含了正確的logcat ...錯誤傳遞的TextView值
我正在寫一個應用程序，將允許用戶輸入值，它們將用於在圖表上繪圖。最近幾天，我一直被困在一個特定的問題上，似乎無法克服它。用戶將輸入2個值，並從這3個值中計算出來並傳遞給內部類以在圖表上繪製。這些值是TextView窗體的值。我知道大部分代碼的工作原理是我一直在測試它，而且我很確定這個錯誤與TextView值有關。以下是用於計算和繪製圖表的代碼。
package com.example.ballanimation;
import java.math.BigDecimal;
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class calculations extends Activity {
EditText firstVal, secondVal;
TextView resultA, resultB, resultC;
Button button3;
BigDecimal firstNum, secNum;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.calculations_page);
button3 = (Button) findViewById(R.id.button3);
firstVal = (EditText) findViewById(R.id.editTXT1);
secondVal = (EditText) findViewById(R.id.editTXT2);
resultA = (TextView) findViewById(R.id.result1);
resultB = (TextView) findViewById(R.id.result2);
resultC = (TextView) findViewById(R.id.result3);
button3.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
firstNum = new BigDecimal(firstVal.getText().toString());
secNum = new BigDecimal(secondVal.getText().toString());
resultA.setText(firstNum.add(secNum).toString());
resultB.setText(firstNum.subtract(secNum).toString());
resultC.setText(firstNum.multiply(secNum).toString());
}
});
}
class TestA1 extends View{
public TestA1(Context context) {
super(context);
// TODO Auto-generated constructor stub
}
public void onDraw(Canvas canvas){
super.onDraw(canvas);
String TestA = resultA.getText().toString();
String TestB = resultB.getText().toString();
String TestC = resultC.getText().toString();
int A = Integer.parseInt(TestA);
int B = Integer.parseInt(TestB);
int C = Integer.parseInt(TestC);
Paint red = new Paint();
red.setColor(Color.RED);
red.setStyle(Paint.Style.STROKE);
Paint black = new Paint();
black.setColor(Color.BLACK);
black.setStyle(Paint.Style.STROKE);
canvas.drawCircle(A, B, C, black);
canvas.drawCircle(canvas.getWidth()*1/2, canvas.getHeight()*3/8, canvas.getWidth()*475/1000, black);
canvas.drawCircle(canvas.getWidth()*5/8, canvas.getWidth()*5/8, canvas.getWidth()*349/1000, black);
canvas.drawCircle(canvas.getWidth()*6/8, canvas.getWidth()*5/8, canvas.getWidth()*228/1000, black);
canvas.drawCircle(canvas.getWidth()*7/8, canvas.getWidth()*5/8, canvas.getWidth()*103/1000, black);
canvas.drawLine((canvas.getWidth()-canvas.getWidth()) + 10, (canvas.getHeight()*3)/8, canvas.getWidth() - 10, (canvas.getHeight()*3)/8, black);
float a, b, c, d, e, f, g, h, i, j, k, l;
a = 90; //degrees
b = 90;
c = 90;
d = 50;
e = 90;
f = 134;
g = -90;
h = -90;
i = -90;
j = -50;
k = -90;
l = -134;
RectF arc0 = new RectF();
RectF arc1 = new RectF();
RectF arc2 = new RectF();
RectF arc3 = new RectF();
RectF arc4 = new RectF();
RectF arc5 = new RectF();
/*left The X coordinate of the left side of the rectangle
top The Y coordinate of the top of the rectangle
right The X coordinate of the right side of the rectangle
bottom The Y coordinate of the bottom of the rectangle */
arc0.set(canvas.getWidth()*1/2, canvas.getHeight()*-139/700, canvas.getWidth()*100/69, canvas.getHeight()*3/8);
arc1.set(canvas.getWidth()*-6/112, canvas.getHeight()*-80/100, canvas.getWidth()*195/100, canvas.getHeight()*72/192);
arc2.set(canvas.getWidth()*7/10, canvas.getHeight()*70/700, canvas.getWidth()*125/100, canvas.getHeight()*3/8);
arc3.set(canvas.getWidth()/2, canvas.getHeight()*3/8, canvas.getWidth()*100/69, canvas.getHeight()*91/96);
arc4.set(canvas.getWidth()*-8/112, canvas.getHeight()*3/8, canvas.getWidth()*195/100, canvas.getHeight()*150/100);
arc5.set(canvas.getWidth()*7/10, canvas.getHeight()*3/8, canvas.getWidth()*125/100, canvas.getHeight()*65/100);
/*oval The bounds of oval used to define the shape and size of the arc
startAngle Starting angle (in degrees) where the arc begins
sweepAngle Sweep angle (in degrees) measured clockwise
useCenter If true, include the center of the oval in the arc, and close it if it is being stroked. This will draw a wedge
paint The paint used to draw the arc */
canvas.drawArc(arc0, a, b, false, red);
canvas.drawArc(arc1, c, d, false, red);
canvas.drawArc(arc2, e, f, false, red);
canvas.drawArc(arc3, g, h, false, red);
canvas.drawArc(arc4, i, j, false, red);
canvas.drawArc(arc5, k, l, false, red);
}
}
}
我得到的logcat的錯誤是：
01-08 11:54:05.436: D/dalvikvm(714): GC_FOR_ALLOC freed 42K, 3% free 8053K/8259K, paused 66ms, total 69ms
01-08 11:54:05.436: I/dalvikvm-heap(714): Grow heap (frag case) to 8.305MB for 412064-byte allocation
01-08 11:54:05.596: D/dalvikvm(714): GC_FOR_ALLOC freed 1K, 3% free 8455K/8711K, paused 55ms, total 55ms
01-08 11:54:05.647: D/dalvikvm(714): GC_FOR_ALLOC freed 0K, 3% free 8455K/8711K, paused 48ms, total 48ms
01-08 11:54:05.666: I/dalvikvm-heap(714): Grow heap (frag case) to 9.189MB for 928216-byte allocation
01-08 11:54:05.836: D/dalvikvm(714): GC_CONCURRENT freed 0K, 4% free 9361K/9671K, paused 98ms+9ms, total 173ms
01-08 11:54:05.836: D/dalvikvm(714): WAIT_FOR_CONCURRENT_GC blocked 3ms
01-08 11:54:06.186: D/gralloc_goldfish(714): Emulator without GPU emulation detected.
01-08 11:54:07.856: I/Choreographer(714): Skipped 79 frames! The application may be doing too much work on its main thread.
01-08 11:54:25.786: D/AndroidRuntime(714): Shutting down VM
01-08 11:54:25.816: W/dalvikvm(714): threadid=1: thread exiting with uncaught exception (group=0x40a13300)
01-08 11:54:25.866: E/AndroidRuntime(714): FATAL EXCEPTION: main
01-08 11:54:25.866: E/AndroidRuntime(714): java.lang.NullPointerException
01-08 11:54:25.866: E/AndroidRuntime(714): at com.example.ballanimation.calculations$TestA1.onDraw(calculations.java:83)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.view.View.draw(View.java:13458)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.view.View.draw(View.java:13342)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.view.ViewGroup.drawChild(ViewGroup.java:2929)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2799)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.view.View.draw(View.java:13461)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.widget.FrameLayout.draw(FrameLayout.java:467)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.view.View.draw(View.java:13342)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.view.ViewGroup.drawChild(ViewGroup.java:2929)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2799)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.view.View.draw(View.java:13340)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.view.ViewGroup.drawChild(ViewGroup.java:2929)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2799)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.view.View.draw(View.java:13461)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.widget.FrameLayout.draw(FrameLayout.java:467)
01-08 11:54:25.866: E/AndroidRuntime(714): at com.android.internal.policy.impl.PhoneWindow$DecorView.draw(PhoneWindow.java:2183)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.view.ViewRootImpl.drawSoftware(ViewRootImpl.java:2256)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.view.ViewRootImpl.draw(ViewRootImpl.java:2151)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.view.ViewRootImpl.performDraw(ViewRootImpl.java:2019)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1830)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:998)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4212)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:725)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.view.Choreographer.doCallbacks(Choreographer.java:555)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.view.Choreographer.doFrame(Choreographer.java:525)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:711)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.os.Handler.handleCallback(Handler.java:615)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.os.Handler.dispatchMessage(Handler.java:92)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.os.Looper.loop(Looper.java:137)
01-08 11:54:25.866: E/AndroidRuntime(714): at android.app.ActivityThread.main(ActivityThread.java:4745)
01-08 11:54:25.866: E/AndroidRuntime(714): at java.lang.reflect.Method.invokeNative(Native Method)
01-08 11:54:25.866: E/AndroidRuntime(714): at java.lang.reflect.Method.invoke(Method.java:511)
01-08 11:54:25.866: E/AndroidRuntime(714): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
01-08 11:54:25.866: E/AndroidRuntime(714): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
01-08 11:54:25.866: E/AndroidRuntime(714): at dalvik.system.NativeStart.main(Native Method)
01-08 11:54:28.535: I/Process(714): Sending signal. PID: 714 SIG: 9
我敢肯定，錯誤被包含在該行的：
String TestA = resultA.getText().toString();
String TestB = resultB.getText().toString();
String TestC = resultC.getText().toString();
一定有什麼錯誤的方式我正在傳遞TextView值，但我無法看到問題出在哪裏。
任何幫助將不勝感激。
'NullPointerException異常01-08 11：54：25.866：E/AndroidRuntime（714）：at com.example.ballanimation.calculations $ TestA1.onDraw（computation.java:83）'哪個是你的onDraw（）函數中的第83行？ –
@你在這行上包含'calculate.java：83'？ –
@PratikSharma嗨感謝您的迴應，第83行包含：String TestA = resultA.getText（）。toString（）; String TestB = resultB.getText（）。toString（）; String TestC = resultC。的getText（）的toString（）; – user1927105