剛學android不久，因為公司項目要求，寫瞭個類似刻度尺的東西，拿出來獻醜，希望大傢給點意見。
先上代碼，註：KeduView中的浮點數計算我沒處理（因為精度問題，浮點數直接計算出來的結果可能不對）。StaffView中的浮點數計算我進行瞭處理，我在Arithmetic中封裝瞭加減乘除方法：
Java代碼
package com.hyx.suiyipaint;
import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Rect;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.widget.ImageView;
import android.widget.LinearLayout;
public class KeduActivity extends Activity {
private ImageView kedu_tiao;
private LinearLayout kedu_linear;
private LinearLayout staff_linear;
private KeduView kedu;
private StaffView staff;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.kedu);
kedu_linear = (LinearLayout)findViewById(R.id.kedu_linear);
kedu = new KeduView(this, 0f, 0.1f);
kedu_linear.addView(kedu);
staff_linear = (LinearLayout)findViewById(R.id.staff_linear);
staff = new StaffView(this, 7.5f, 0.5f, "cm");
staff_linear.addView(staff);
kedu_tiao = (ImageView)findViewById(R.id.kedu_tiao);
kedu_tiao.setOnTouchListener(keduListener);
}
private ImageView.OnTouchListener keduListener = new ImageView.OnTouchListener(){
private float initx = 0;
@Override
public boolean onTouch(View v, MotionEvent event) {
switch(event.getAction()){
case MotionEvent.ACTION_DOWN:
initx = event.getX();
break;
case MotionEvent.ACTION_MOVE:
float lastx = event.getX();
if(lastx > initx + 5){
kedu.draw(1);
initx = lastx;
}else if(lastx < initx -5){
kedu.draw(-1);
initx = lastx;
}
break;
}
return true;
}
};
class KeduView extends SurfaceView implements SurfaceHolder.Callback, Runnable{
private SurfaceHolder mSurfaceHolder = null;
private Canvas canvas;
//畫佈背景
private Bitmap background;
//刻度遊標
private Bitmap pointer;
//總刻度數
private static final int KEDU_COUNT = 25;
//刻度最小值
private float init_min;
//每個刻度的單位值
private float interval;
public KeduView(Context context, float init_min, float interval) {
super(context);
mSurfaceHolder = this.getHolder();
mSurfaceHolder.addCallback(this);
this.setFocusable(true);
background = BitmapFactory.decodeResource(getResources(), R.drawable.kedu_bg);
pointer = BitmapFactory.decodeResource(getResources(), R.drawable.kedu_pointer);
this.init_min = init_min;
this.interval = interval;
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
new Thread(this).start();
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
}
@Override
public void run() {
draw(0);
}
//每次X軸移動的像素
private static final int MOVE = 10;
//遊標在最左邊時X軸的位置
private static final int INIT_POINTER_LEFT = 20;
//遊標在最右邊時X軸的位置
private static final int INIT_POINTER_RIGHT = 270;
//遊標頂端Y軸的位置
private static final int INIT_POINTER_TOP = 36;
//底下刻度數字最左邊的X軸位置
private static final int INIT_NUM_X = 18;
//結果的X軸位置
private static final int RESULT_X = 36;
//結果的Y軸位置
private static final int RESULT_Y = 25;
//結果的字體大小
private static final int RESULT_SIZE = 24;
//遊標X軸的位置
private int POINTER_X = INIT_POINTER_LEFT;
//底下刻度數字X軸位置
private int NUM_X = INIT_NUM_X;
//底下刻度數字的Y軸位置
private int NUM_Y = 85;
//結果
private float result = 0;
/**
* @param direction 方向，-1向左，1向右，0不動
*/
public void draw(int direction){
//獲取畫佈
canvas = mSurfaceHolder.lockCanvas();
if (mSurfaceHolder == null || canvas == null) {
return;
}
canvas.drawColor(Color.WHITE);
Paint paint = new Paint();
paint.setAntiAlias(true);
paint.setColor(Color.GRAY);
canvas.drawBitmap(background, new Matrix(), paint);
switch(direction){
case -1:
POINTER_X -= MOVE;
result -= interval;
if(result <= 0){
result = init_min;
POINTER_X = INIT_POINTER_LEFT;
}else{
if(POINTER_X < INIT_POINTER_LEFT){
POINTER_X = INIT_POINTER_RIGHT;
result = init_min;
init_min -= KEDU_COUNT * interval;
}
}
break;
case 1:
POINTER_X += MOVE;
result += interval;
if(POINTER_X > INIT_POINTER_RIGHT){
POINTER_X = INIT_POINTER_LEFT;
init_min += KEDU_COUNT * interval;
result = init_min;
}
break;
}
canvas.drawBitmap(pointer, POINTER_X, INIT_POINTER_TOP, paint);
for(int i=0; i<6; i++){
if(i == 0){
NUM_X = INIT_NUM_X;
}
canvas.drawText(Float.toString(i * 5f * interval + init_min), NUM_X, NUM_Y, paint);
NUM_X += 50;
}
paint.setColor(Color.BLACK);
paint.setTextSize(RESULT_SIZE);
canvas.drawText(Float.toString(result), RESULT_X, RESULT_Y, paint);
//解鎖畫佈，提交畫好的圖像
mSurfaceHolder.unlockCanvasAndPost(canvas);
}
}
class StaffView extends SurfaceView implements SurfaceHolder.Callback, Runnable{
private SurfaceHolder mSurfaceHolder = null;
private Canvas canvas;
private Paint paint;
//畫佈背景
private Bitmap background;
//刻度
private Bitmap staff;
//刻度遊標
private Bitmap pointer;
//初始值
private float initValue;
//刻度單位最小值
private float interval;
//單位
private String unit;
//是否初始
private boolean isInit = true;
public StaffView(Context context, float initValue, float interval, String unit) {
super(context);
mSurfaceHolder = this.getHolder();
mSurfaceHolder.addCallback(this);
paint = new Paint();
this.setFocusable(true);
background = BitmapFactory.decodeResource(getResources(), R.drawable.staff_bg);
staff = BitmapFactory.decodeResource(getResources(), R.drawable.staff0);
pointer = BitmapFactory.decodeResource(getResources(), R.drawable.kedu_pointer);
this.initValue = initValue;
this.interval = interval;
this.unit = unit;
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
new Thread(this).start();
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
}
@Override
public void run() {
draw(0);
}
private int move = 10; //每次移動的距離
private int initBx = 77; //圖片上X坐標
private int by = 0; //圖片上Y坐標
private int bw = 258; //圖片寬度
private int bh = 31; //圖片高度
private int sx = 18; //畫佈X坐標
private int sy = 36; //畫佈Y坐標
private int jiange = 51; //大刻度之間距離
private int num_left = 33; //最左邊數字到左邊的距離
private int RESULT_X = 36; //結果的X軸位置
private int RESULT_Y = 25; //結果的Y軸位置
private int RESULT_SIZE = 24; //結果的字體大小
private float result = 0;
/**
* @param direction 方向，-1向左，1向右，0不動
*/
public void draw(int direction){
//獲取畫佈
canvas = mSurfaceHolder.lockCanvas();
if (mSurfaceHolder == null || canvas == null) {
return;
}
canvas.drawColor(Color.WHITE);
paint.setAntiAlias(true);
paint.setColor(Color.GRAY);
canvas.drawBitmap(background, new Matrix(), paint);
if(isInit){
result = initValue;
}else{
switch(direction){
case 1:
result = Arithmetic.add(result, interval);
break;
case -1:
result = Arithmetic.sub(result, interval);
if(result < 0){
result = 0;
}
break;
}
}
initStaff();
canvas.drawBitmap(pointer, 143, 36, paint);
Paint reslutPaint = new Paint();
reslutPaint.setColor(Color.BLACK);
reslutPaint.setTextSize(RESULT_SIZE);
canvas.drawText(Float.toString(result) + " " + unit, RESULT_X, RESULT_Y, reslutPaint);
//解鎖畫佈，提交畫好的圖像
mSurfaceHolder.unlockCanvasAndPost(canvas);
}
private void initStaff(){
int bx = initBx;
int num_x = num_left;
int mod = 0;
int midd = 2;
if(result != 0){
mod = (int)(Arithmetic.p(result, interval, 1) % 5);
bx += mod * move;
}
if(mod >= 3){
midd = 1;
num_x += (5 – mod) * move;
}else{
num_x -= mod * move;
}
float text = 0;
for(int i=0; i<5; i++){
if(i < midd){
text = result – mod * interval – (midd – i) * 5 * interval;
}else if(i == midd){
text = result – mod * interval;
}else{
text += 5 * interval;
}
text = Arithmetic.round(text, 1);
if(text >= 0){
canvas.drawText(Float.toString(text), num_x, 85, paint);
}
num_x += jiange;
}
//要繪制的圖片矩形區域設置
Rect src = new Rect();
src.left = bx;
src.top = by;
src.right = bx + bw;
src.bottom = bh;
//要繪制的畫佈矩形區域設置
Rect dst = new Rect();
dst.left = sx;
dst.top = sy;
dst.right = sx + bw;
dst.bottom = sy + bh;
canvas.drawBitmap(staff, src, dst, paint);
}
private float initx = 0;
@Override
public boolean onTouchEvent(MotionEvent event) {
switch(event.getAction()){
case MotionEvent.ACTION_DOWN:
initx = event.getX();
break;
case MotionEvent.ACTION_MOVE:
float lastx = event.getX();
if(lastx > initx + 5){
isInit = false;
draw(-1);
initx = lastx;
}else if(lastx < initx -5){
isInit = false;
draw(1);
initx = lastx;
}
break;
}
return true;
}
public float getResult(){
return result;
}
}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if(keyCode == KeyEvent.KEYCODE_VOLUME_DOWN){
staff.isInit = false;
staff.draw(-1);
return true;
}if(keyCode == KeyEvent.KEYCODE_VOLUME_UP){
staff.isInit = false;
staff.draw(1);
return true;
}
return super.onKeyDown(keyCode, event);
}
}
佈局文件：
Xml代碼
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center"
android:background="#fff">
<LinearLayout
android:id="@+id/kedu_linear"
android:layout_width="294dp"
android:layout_height="101dp"/>
<ImageView
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:id="@+id/kedu_tiao"
android:src="@drawable/kedu_wheel_01"
android:layout_margin="20dp"/>
<LinearLayout
android:id="@+id/staff_linear"
android:layout_width="294dp"
android:layout_height="101dp"/>
</LinearLayout>
附件是運行效果截圖。