您好我实际上是按照此链接创建了一个仪表视图。
http://mindtherobot.com/blog/272/android-custom-ui-making-a-vintage-thermometer/
但是当我在模拟器中运行代码时，仪表的读数变为零，我无法找出原因。什么可能出错的线索？我打印了函数drawscale的“i”值，结果很好，但是当我运行模拟器时，gauview中的读数总是为零。
package com.mindtherobot.samples.thermometer;
import java.util.List;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.LightingColorFilter;
import android.graphics.LinearGradient;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.RadialGradient;
import android.graphics.RectF;
import android.graphics.Shader;
import android.graphics.Typeface;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.os.Handler;
import android.os.Parcelable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;
public final class Thermometer extends View implements SensorEventListener {
private static final String TAG = Thermometer.class.getSimpleName();
private Handler handler;
// drawing tools
private RectF rimRect;
private Paint rimPaint;
private Paint rimCirclePaint;
private RectF faceRect;
private Bitmap faceTexture;
private Paint facePaint;
private Paint rimShadowPaint;
private Paint scalePaint;
private RectF scaleRect;
private Paint titlePaint;
private Path titlePath;
private Paint logoPaint;
private Bitmap logo;
private Matrix logoMatrix;
private float logoScale;
private Paint handPaint;
private Path handPath;
private Paint handScrewPaint;
private Paint backgroundPaint;
// end drawing tools
private Bitmap background; // holds the cached static part
// scale configuration
private int totalNotches = 100;
private int incrementPerLargeNotch = 10;
private int incrementPerSmallNotch = 2;
private float degreesPerNotch = 360.0f / totalNotches;
private int scaleCenterValue = 40; // the one in the top center (12 o'clock)
private int scaleMinValue = -30;
private int scaleMaxValue = 110;
// hand dynamics -- all are angular expressed in F degrees
private boolean handInitialized = false;
private float handPosition = scaleCenterValue;
private float handTarget = scaleCenterValue;
private float handVelocity = 0.0f;
private float handAcceleration = 0.0f;
private long lastHandMoveTime = -1L;
public Thermometer(Context context) {
super(context);
init();
}
public Thermometer(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public Thermometer(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init();
}
@Override
protected void onAttachedToWindow() {
super.onAttachedToWindow();
attachToSensor();
}
@Override
protected void onDetachedFromWindow() {
detachFromSensor();
super.onDetachedFromWindow();
}
@Override
protected void onRestoreInstanceState(Parcelable state) {
Bundle bundle = (Bundle) state;
Parcelable superState = bundle.getParcelable("superState");
super.onRestoreInstanceState(superState);
handInitialized = bundle.getBoolean("handInitialized");
handPosition = bundle.getFloat("handPosition");
handTarget = bundle.getFloat("handTarget");
handVelocity = bundle.getFloat("handVelocity");
handAcceleration = bundle.getFloat("handAcceleration");
lastHandMoveTime = bundle.getLong("lastHandMoveTime");
}
@Override
protected Parcelable onSaveInstanceState() {
Parcelable superState = super.onSaveInstanceState();
Bundle state = new Bundle();
state.putParcelable("superState", superState);
state.putBoolean("handInitialized", handInitialized);
state.putFloat("handPosition", handPosition);
state.putFloat("handTarget", handTarget);
state.putFloat("handVelocity", handVelocity);
state.putFloat("handAcceleration", handAcceleration);
state.putLong("lastHandMoveTime", lastHandMoveTime);
return state;
}
private void init() {
handler = new Handler();
initDrawingTools();
}
private String getTitle() {
return "mindtherobot.com";
}
private SensorManager getSensorManager() {
return (SensorManager) getContext().getSystemService(Context.SENSOR_SERVICE);
}
private void attachToSensor() {
SensorManager sensorManager = getSensorManager();
List<Sensor> sensors = sensorManager.getSensorList(Sensor.TYPE_TEMPERATURE);
if (sensors.size() > 0) {
Sensor sensor = sensors.get(0);
sensorManager.registerListener(this, sensor, SensorManager.SENSOR_DELAY_FASTEST, handler);
} else {
Log.e(TAG, "No temperature sensor found");
}
}
private void detachFromSensor() {
SensorManager sensorManager = getSensorManager();
sensorManager.unregisterListener(this);
}
private void initDrawingTools() {
rimRect = new RectF(0.1f, 0.1f, 0.9f, 0.9f);
// the linear gradient is a bit skewed for realism
rimPaint = new Paint();
rimPaint.setFlags(Paint.ANTI_ALIAS_FLAG);
rimPaint.setShader(new LinearGradient(0.40f, 0.0f, 0.60f, 1.0f,
Color.rgb(0xf0, 0xf5, 0xf0),
Color.rgb(0x30, 0x31, 0x30),
Shader.TileMode.CLAMP));
rimCirclePaint = new Paint();
rimCirclePaint.setAntiAlias(true);
rimCirclePaint.setStyle(Paint.Style.STROKE);
rimCirclePaint.setColor(Color.argb(0x4f, 0x33, 0x36, 0x33));
rimCirclePaint.setStrokeWidth(0.005f);
float rimSize = 0.02f;
faceRect = new RectF();
faceRect.set(rimRect.left + rimSize, rimRect.top + rimSize,
rimRect.right - rimSize, rimRect.bottom - rimSize);
faceTexture = BitmapFactory.decodeResource(getContext().getResources(),
R.drawable.plastic);
BitmapShader paperShader = new BitmapShader(faceTexture,
Shader.TileMode.MIRROR,
Shader.TileMode.MIRROR);
Matrix paperMatrix = new Matrix();
facePaint = new Paint();
facePaint.setFilterBitmap(true);
paperMatrix.setScale(1.0f / faceTexture.getWidth(),
1.0f / faceTexture.getHeight());
paperShader.setLocalMatrix(paperMatrix);
facePaint.setStyle(Paint.Style.FILL);
facePaint.setShader(paperShader);
rimShadowPaint = new Paint();
rimShadowPaint.setShader(new RadialGradient(0.5f, 0.5f, faceRect.width() / 2.0f,
new int[] { 0x00000000, 0x00000500, 0x50000500 },
new float[] { 0.96f, 0.96f, 0.99f },
Shader.TileMode.MIRROR));
rimShadowPaint.setStyle(Paint.Style.FILL);
scalePaint = new Paint();
scalePaint.setStyle(Paint.Style.STROKE);
scalePaint.setColor(0x9f004d0f);
scalePaint.setStrokeWidth(0.005f);
scalePaint.setAntiAlias(true);
scalePaint.setTextSize(0.045f);
scalePaint.setTypeface(Typeface.SANS_SERIF);
scalePaint.setTextScaleX(0.8f);
scalePaint.setTextAlign(Paint.Align.CENTER);
float scalePosition = 0.10f;
scaleRect = new RectF();
scaleRect.set(faceRect.left + scalePosition, faceRect.top + scalePosition,
faceRect.right - scalePosition, faceRect.bottom - scalePosition);
titlePaint = new Paint();
titlePaint.setColor(0xaf946109);
titlePaint.setAntiAlias(true);
titlePaint.setTypeface(Typeface.DEFAULT_BOLD);
titlePaint.setTextAlign(Paint.Align.CENTER);
titlePaint.setTextSize(0.05f);
titlePaint.setTextScaleX(0.8f);
titlePath = new Path();
titlePath.addArc(new RectF(0.24f, 0.24f, 0.76f, 0.76f), -180.0f, -180.0f);
logoPaint = new Paint();
logoPaint.setFilterBitmap(true);
logo = BitmapFactory.decodeResource(getContext().getResources(), R.drawable.logo);
logoMatrix = new Matrix();
logoScale = (1.0f / logo.getWidth()) * 0.3f;;
logoMatrix.setScale(logoScale, logoScale);
handPaint = new Paint();
handPaint.setAntiAlias(true);
handPaint.setColor(0xff392f2c);
handPaint.setShadowLayer(0.01f, -0.005f, -0.005f, 0x7f000000);
handPaint.setStyle(Paint.Style.FILL);
handPath = new Path();
handPath.moveTo(0.5f, 0.5f + 0.2f);
handPath.lineTo(0.5f - 0.010f, 0.5f + 0.2f - 0.007f);
handPath.lineTo(0.5f - 0.002f, 0.5f - 0.32f);
handPath.lineTo(0.5f + 0.002f, 0.5f - 0.32f);
handPath.lineTo(0.5f + 0.010f, 0.5f + 0.2f - 0.007f);
handPath.lineTo(0.5f, 0.5f + 0.2f);
handPath.addCircle(0.5f, 0.5f, 0.025f, Path.Direction.CW);
handScrewPaint = new Paint();
handScrewPaint.setAntiAlias(true);
handScrewPaint.setColor(0xff493f3c);
handScrewPaint.setStyle(Paint.Style.FILL);
backgroundPaint = new Paint();
backgroundPaint.setFilterBitmap(true);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
Log.d(TAG, "Width spec: " + MeasureSpec.toString(widthMeasureSpec));
Log.d(TAG, "Height spec: " + MeasureSpec.toString(heightMeasureSpec));
int widthMode = MeasureSpec.getMode(widthMeasureSpec);
int widthSize = MeasureSpec.getSize(widthMeasureSpec);
int heightMode = MeasureSpec.getMode(heightMeasureSpec);
int heightSize = MeasureSpec.getSize(heightMeasureSpec);
int chosenWidth = chooseDimension(widthMode, widthSize);
int chosenHeight = chooseDimension(heightMode, heightSize);
int chosenDimension = Math.min(chosenWidth, chosenHeight);
setMeasuredDimension(chosenDimension, chosenDimension);
}
private int chooseDimension(int mode, int size) {
if (mode == MeasureSpec.AT_MOST || mode == MeasureSpec.EXACTLY) {
return size;
} else { // (mode == MeasureSpec.UNSPECIFIED)
return getPreferredSize();
}
}
// in case there is no size specified
private int getPreferredSize() {
return 300;
}
private void drawRim(Canvas canvas) {
// first, draw the metallic body
canvas.drawOval(rimRect, rimPaint);
// now the outer rim circle
canvas.drawOval(rimRect, rimCirclePaint);
}
private void drawFace(Canvas canvas) {
canvas.drawOval(faceRect, facePaint);
// draw the inner rim circle
canvas.drawOval(faceRect, rimCirclePaint);
// draw the rim shadow inside the face
canvas.drawOval(faceRect, rimShadowPaint);
}
private void drawScale(Canvas canvas) {
// Draw a large notch every large increment, and a small
// notch every small increment.
canvas.drawOval(scaleRect, scalePaint);
canvas.save(Canvas.MATRIX_SAVE_FLAG);
for (int i = 0; i < totalNotches; ++i) {
float y1 = scaleRect.top;
float y2 = y1 - 0.015f;
float y3 = y1 - 0.025f;
System.out.println("The value of i is "+i);
int value = notchToValue(i);
System.out.println("The value of value is "+value);
if (i % (incrementPerLargeNotch/incrementPerSmallNotch) == 0) {
System.out.println("inside loop i"+i);
if (value >= scaleMinValue && value <= scaleMaxValue) {
// draw a nick
canvas.drawLine(0.5f, y1, 0.5f, y3, scalePaint);
String valueString = Integer.toString(value);
System.out.println("the value of value string is "+valueString);
// Draw the text 0.15 away from y3 which is the long nick.
canvas.drawText(valueString, 0.5f, y3 - 0.015f, scalePaint);
}
}
else{
if (value >= scaleMinValue && value <= scaleMaxValue) {
// draw a nick
canvas.drawLine(0.5f, y1, 0.5f, y2, scalePaint);
}
}
canvas.rotate(degreesPerNotch, 0.5f, 0.5f);
}
canvas.restore();
}
private int notchToValue(int value) {
int rawValue = ((value < totalNotches / 2) ? value : (value - totalNotches)) * incrementPerSmallNotch;
int shiftedValue = rawValue + scaleCenterValue;
return shiftedValue;
}
private float valueToAngle(float value) {
return (value - scaleCenterValue) / 2.0f * degreesPerNotch;
}
private void drawTitle(Canvas canvas) {
String title = getTitle();
canvas.drawTextOnPath(title, titlePath, 0.0f,0.0f, titlePaint);
}
private void drawLogo(Canvas canvas) {
canvas.save(Canvas.MATRIX_SAVE_FLAG);
canvas.translate(0.5f - logo.getWidth() * logoScale / 2.0f,
0.5f - logo.getHeight() * logoScale / 2.0f);
int color = 0x00000000;
float position = getRelativeTemperaturePosition();
if (position < 0) {
color |= (int) ((0xf0) * -position); // blue
} else {
color |= ((int) ((0xf0) * position)) << 16; // red
}
//Log.d(TAG, "*** " + Integer.toHexString(color));
LightingColorFilter logoFilter = new LightingColorFilter(0xff338822, color);
logoPaint.setColorFilter(logoFilter);
canvas.drawBitmap(logo, logoMatrix, logoPaint);
canvas.restore();
}
private void drawHand(Canvas canvas) {
if (handInitialized) {
float handAngle = valueToAngle(handPosition);
canvas.save(Canvas.MATRIX_SAVE_FLAG);
canvas.rotate(handAngle, 0.5f, 0.5f);
canvas.drawPath(handPath, handPaint);
canvas.restore();
canvas.drawCircle(0.5f, 0.5f, 0.01f, handScrewPaint);
}
}
private void drawBackground(Canvas canvas) {
if (background == null) {
Log.w(TAG, "Background not created");
} else {
canvas.drawBitmap(background, 0, 0, backgroundPaint);
}
}
@Override
protected void onDraw(Canvas canvas) {
drawBackground(canvas);
float scale = (float) getWidth();
canvas.save(Canvas.MATRIX_SAVE_FLAG);
canvas.scale(scale, scale);
drawLogo(canvas);
drawHand(canvas);
canvas.restore();
if (handNeedsToMove()) {
moveHand();
}
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
Log.d(TAG, "Size changed to " + w + "x" + h);
regenerateBackground();
}
private void regenerateBackground() {
// free the old bitmap
if (background != null) {
background.recycle();
}
background = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888);
Canvas backgroundCanvas = new Canvas(background);
float scale = (float) getWidth();
backgroundCanvas.scale(scale, scale);
drawRim(backgroundCanvas);
drawFace(backgroundCanvas);
drawScale(backgroundCanvas);
drawTitle(backgroundCanvas);
}
private boolean handNeedsToMove() {
return Math.abs(handPosition - handTarget) > 0.01f;
}
private void moveHand() {
if (! handNeedsToMove()) {
return;
}
if (lastHandMoveTime != -1L) {
long currentTime = System.currentTimeMillis();
float delta = (currentTime - lastHandMoveTime) / 1000.0f;
float direction = Math.signum(handVelocity);
if (Math.abs(handVelocity) < 90.0f) {
handAcceleration = 5.0f * (handTarget - handPosition);
} else {
handAcceleration = 0.0f;
}
handPosition += handVelocity * delta;
handVelocity += handAcceleration * delta;
if ((handTarget - handPosition) * direction < 0.01f * direction) {
handPosition = handTarget;
handVelocity = 0.0f;
handAcceleration = 0.0f;
lastHandMoveTime = -1L;
} else {
lastHandMoveTime = System.currentTimeMillis();
}
invalidate();
} else {
lastHandMoveTime = System.currentTimeMillis();
moveHand();
}
}
@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
@Override
public void onSensorChanged(SensorEvent sensorEvent) {
if (sensorEvent.values.length > 0) {
float temperatureC = sensorEvent.values[0];
//Log.i(TAG, "*** Temperature: " + temperatureC);
float temperatureF = (9.0f / 5.0f) * temperatureC + 32.0f;
setHandTarget(temperatureF);
} else {
Log.w(TAG, "Empty sensor event received");
}
}
private float getRelativeTemperaturePosition() {
if (handPosition < scaleCenterValue) {
return - (scaleCenterValue - handPosition) / (float) (scaleCenterValue - scaleMinValue);
} else {
return (handPosition - scaleCenterValue) / (float) (scaleMaxValue - scaleCenterValue);
}
}
private void setHandTarget(float temperature) {
if (temperature < scaleMinValue) {
temperature = scaleMinValue;
} else if (temperature > scaleMaxValue) {
temperature = scaleMaxValue;
}
handTarget = temperature;
handInitialized = true;
invalidate();
}
}
答案 0 :(得分：3)
我知道这是一个老问题，但昨天我遇到了同样的问题。
我认为OP所描述的是，比例尺上显示的所有数字值都显示为0。将setLinearText(true)设为scalePaint会更正此问题。
答案 1 :(得分：0)
出了什么问题？ 如果你的意思是为什么温度计没有显示任何值，那是因为程序正在使用SensorManager来接收TEMPERATURE值。 由于仿真器没有，因此返回的值始终为零。
答案 2 :(得分：0)
是的，我在initDrawingTools()的所有集合之后将此行添加到scalePaint方法。
scalePaint.setLinearText(true);
它有效！