实现一个彩虹色进度条功能,不说明具体用途大家应该能猜到。想找别人造的轮子,但是没有合适的,所以决定自己实现一个。
android 自定义view
LinearGradient 线性渐变
自定义一个TmcView类继承View
重写两个构造方法。构造方法一共有4个,这里边重写两个
重写ongSizeChanged方法,用来获取控件宽、高,来计算内部组件尺寸。
重写onDraw方法,里边要描画背景drawBackground,分段数据drawSection,和seekbar图片drawImage。
- import android.content.Context;
- import android.graphics.Canvas;
- import android.util.AttributeSet;
- import android.view.View;
-
- import androidx.annotation.Nullable;
-
- import java.util.List;
-
- public class TmcView extends View {
-
- public TmcView(Context context) {
- super(context);
- }
-
- public TmcView(Context context, @Nullable AttributeSet attrs) {
- super(context, attrs);
- }
-
- @Override
- protected void onSizeChanged(int w, int h, int oldw, int oldh) {
- super.onSizeChanged(w, h, oldw, oldh);
- }
-
-
- @Override
- protected void onDraw(Canvas canvas) {
- super.onDraw(canvas);
- drawBackground(canvas);
- drawSection(canvas);
- drawImage(canvas);
- }
-
- /**
- * 画背景
- * @param canvas 画布
- */
- private void drawBackground(Canvas canvas) {
- }
-
- /**
- * 画分段数据
- * @param canvas 画布
- */
- private void drawSection(Canvas canvas) {
- }
-
- /**
- * 画图片
- * @param canvas 画布
- */
- private void drawImage(Canvas canvas) {
- }
-
- /**
- * 更新view
- * @param total 总长度
- * @param rest 剩余长度
- * @param sections 分段数据
- */
- public void updateView(int total, int rest, List
sections) { -
- }
标注:
整体宽度为图片宽度44px
背景条宽度30px,外边距7px,圆角15px
带颜色的条宽度20xp,外边距5px,圆角15px
自定义view的坐标轴是以view的左上角位置为原点,向右为x轴正方向,向下为y轴正方向
在视图中用RectF创建背景,和颜色条,并在onSizeChanged中设置尺寸
- public class TmcView extends View {
-
- private final RectF backgroundRectF = new RectF();
-
- private final RectF colorRectF = new RectF();
-
- public TmcView(Context context) {
- super(context);
- }
-
- public TmcView(Context context, @Nullable AttributeSet attrs) {
- super(context, attrs);
- }
-
- @Override
- protected void onSizeChanged(int w, int h, int oldw, int oldh) {
- super.onSizeChanged(w, h, oldw, oldh);
- //设置矩形 left top right bottom 左上右下点的值 按照标注计算得出
- backgroundRectF.set(7, 0, 37, h);
- colorRectF.set(12, 5, 32, h-5);
- }
- ...
- }
实现drawBackground方法,画背景需要一根画笔Paint 为了避免重复创建,声明为成员变量
- public class TmcView extends View {
-
- /*背景画笔*/
- private final Paint backPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
-
- private final RectF backgroundRectF = new RectF();
-
- private final RectF colorRectF = new RectF();
-
- public TmcView(Context context) {
- super(context);
- }
-
- public TmcView(Context context, @Nullable AttributeSet attrs) {
- super(context, attrs);
- }
-
- @Override
- protected void onSizeChanged(int w, int h, int oldw, int oldh) {
- super.onSizeChanged(w, h, oldw, oldh);
- //设置矩形 left top right bottom 左上右下点的值 按照标注计算得出
- backgroundRectF.set(7, 0, 37, h);
- colorRectF.set(12, 5, 32, h-5);
- }
-
-
- @Override
- protected void onDraw(Canvas canvas) {
- super.onDraw(canvas);
- drawBackground(canvas);
- drawSection(canvas);
- drawImage(canvas);
- }
-
- /**
- * 画背景
- * @param canvas 画布
- */
- private void drawBackground(Canvas canvas) {
- backPaint.setStyle(Paint.Style.FILL);
- backPaint.setAntiAlias(true); //抗锯齿
- backPaint.setColor(Color.parseColor("#FFFFFF"));
- //画圆角矩形,15为圆角的角度
- canvas.drawRoundRect(backgroundRectF, 15, 15, backPaint);
- }
- ...
- }
布局中加入TmcView
- <com.bigxuan.tesapp.view.TmcView
- android:id="@+id/tmc"
- android:layout_width="44px"
- android:layout_height="690px"
- android:layout_marginEnd="1230px"
- android:layout_marginBottom="100px"
- app:layout_constraintBottom_toBottomOf="parent"
- app:layout_constraintEnd_toEndOf="parent"
- />
实现drawSection方法,这里要用到线性渐变LinearGradient
LinearGradient 简单说,指定每一段的颜色和位置百分比,就能实现每一段显示不同颜色。
但它默认是渐变色,要想不变就在每一段的开始和结束位置都设置相同的颜色。
再创建一个画笔 Paint,画颜色条
- public class TmcView extends View {
-
-
- private final Paint backPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
-
- private final Paint colorPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
-
- private final RectF backgroundRectF = new RectF();
-
- private final RectF colorRectF = new RectF();
-
- public TmcView(Context context) {
- super(context);
- }
-
- public TmcView(Context context, @Nullable AttributeSet attrs) {
- super(context, attrs);
- }
-
- @Override
- protected void onSizeChanged(int w, int h, int oldw, int oldh) {
- super.onSizeChanged(w, h, oldw, oldh);
- //设置矩形 left top right bottom 左上右下点的值 按照标注计算得出
- backgroundRectF.set(7, 0, 37, h);
- colorRectF.set(12, 5, 32, h-5);
- }
-
-
- @Override
- protected void onDraw(Canvas canvas) {
- super.onDraw(canvas);
- drawBackground(canvas);
- drawSection(canvas);
- drawImage(canvas);
- }
-
- /**
- * 画背景
- * @param canvas 画布
- */
- private void drawBackground(Canvas canvas) {
- backPaint.setStyle(Paint.Style.FILL);
- backPaint.setAntiAlias(true); //抗锯齿
- backPaint.setColor(Color.parseColor("#FFFFFF"));
- //画圆角矩形,15为圆角的角度
- canvas.drawRoundRect(backgroundRectF, 15, 15, backPaint);
- }
-
- /**
- * 画分段数据
- * @param canvas 画布
- */
- private void drawSection(Canvas canvas) {
- int[] colorArray = {
- Color.parseColor("#FF0000"), Color.parseColor("#FF0000"),
- Color.parseColor("#00FF00"), Color.parseColor("#00FF00"),
- Color.parseColor("#0000FF"), Color.parseColor("#0000FF")
- };
- float[] positionArray = {
- 0f, 0.2f,
- 0.2f, 0.6f,
- 0.6f, 1f
- };
- colorPaint.setStyle(Paint.Style.FILL);
- colorPaint.setAntiAlias(true);
-
- //指定渐变色方向x轴方向不变,沿y方向渐变,渐变范围为 颜色条高度
- colorPaint.setShader(new LinearGradient(0, 0, 0, colorRectF.bottom, colorArray, positionArray, Shader.TileMode.REPEAT));
- canvas.drawRoundRect(colorRectF,15, 15, colorPaint);
- }
-
- ...
- }
app加入图片资源,根据资源id获取bitmap对象,绘制。
需要注意的是,坐标轴的顶点在左上角,绘制图片时也是以图片左上顶点位置做定位,图片位置是view的高度减掉图片的高度,才能显示在正确位置。
- public class TmcView extends View {
-
- private Context context;
-
- private final Paint backPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
-
- private final Paint colorPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
-
- private final RectF backgroundRectF = new RectF();
-
- private final RectF colorRectF = new RectF();
-
- /*图片资源id*/
- private int imgResId;
-
- /*图片位置*/
- private int imgPos;
-
- public TmcView(Context context) {
- super(context);
- }
-
- public TmcView(Context context, @Nullable AttributeSet attrs) {
- super(context, attrs);
- this.context = context;
- this.imgResId = R.drawable.icon_seekbar_day;
- }
-
- @Override
- protected void onSizeChanged(int w, int h, int oldw, int oldh) {
- super.onSizeChanged(w, h, oldw, oldh);
- //设置矩形 left top right bottom 左上右下点的值 按照标注计算得出
- backgroundRectF.set(7, 0, 37, h);
- colorRectF.set(12, 5, 32, h-5);
- imgPos = h - 44; // 设置一个初始位置
- }
-
-
- @Override
- protected void onDraw(Canvas canvas) {
- super.onDraw(canvas);
- drawBackground(canvas);
- drawSection(canvas);
- drawImage(canvas);
- }
-
- /**
- * 画背景
- * @param canvas 画布
- */
- private void drawBackground(Canvas canvas) {
- backPaint.setStyle(Paint.Style.FILL);
- backPaint.setAntiAlias(true); //抗锯齿
- backPaint.setColor(Color.parseColor("#FFFFFF"));
- //画圆角矩形,15为圆角的角度
- canvas.drawRoundRect(backgroundRectF, 15, 15, backPaint);
- }
-
- /**
- * 画分段数据
- * @param canvas 画布
- */
- private void drawSection(Canvas canvas) {
- int[] colorArray = {
- Color.parseColor("#FF0000"), Color.parseColor("#FF0000"),
- Color.parseColor("#00FF00"), Color.parseColor("#00FF00"),
- Color.parseColor("#0000FF"), Color.parseColor("#0000FF")
- };
- float[] positionArray = {
- 0f, 0.2f,
- 0.2f, 0.6f,
- 0.6f, 1f
- };
- colorPaint.setStyle(Paint.Style.FILL);
- colorPaint.setAntiAlias(true);
-
- //指定渐变色方向x轴方向不变,沿y方向渐变,渐变范围为 颜色条高度
- colorPaint.setShader(new LinearGradient(0, 0, 0, colorRectF.bottom, colorArray, positionArray, Shader.TileMode.REPEAT));
- canvas.drawRoundRect(colorRectF,15, 15, colorPaint);
- }
-
- /**
- * 画图片
- * @param canvas 画布
- */
- private void drawImage(Canvas canvas) {
- Bitmap bitmap = initBitmap(imgResId);
- canvas.save();
- canvas.translate(0, 0);
- canvas.drawBitmap(bitmap, 0, imgPos, null);
- canvas.restore();
- }
-
- /**
- * 通过资源id 创建bitmap
- * @param resId 资源id
- * @return
- */
- private Bitmap initBitmap(int resId) {
- Bitmap originalBmp = BitmapFactory.decodeResource(context.getResources(), resId);
- return Bitmap.createScaledBitmap(originalBmp, 44, 44, true);
- }
- ...
- }
暴露方法用来更新进度updateView
定义一个图片有效的运动距离为view高度减掉图片高度,函数参数为总距离和剩余距离,计算百分比后乘以有效运动距离得出图片描画位置。最后调用invalidate方法刷新view
- import android.content.Context;
- import android.graphics.Bitmap;
- import android.graphics.BitmapFactory;
- import android.graphics.Canvas;
- import android.graphics.Color;
- import android.graphics.LinearGradient;
- import android.graphics.Paint;
- import android.graphics.RectF;
- import android.graphics.Shader;
- import android.util.AttributeSet;
- import android.view.View;
-
- import androidx.annotation.Nullable;
-
- import com.navinfo.tesapp.R;
-
- import java.util.List;
-
- public class TmcView extends View {
-
- private Context context;
-
- private final Paint backPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
-
- private final Paint colorPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
-
- private final RectF backgroundRectF = new RectF();
-
- private final RectF colorRectF = new RectF();
-
- /*图片资源id*/
- private int imgResId;
-
- /*图片位置*/
- private int imgPos;
-
- /*图片有效的运动距离*/
- private int imgValidHeight;
-
- public TmcView(Context context) {
- super(context);
- }
-
- public TmcView(Context context, @Nullable AttributeSet attrs) {
- super(context, attrs);
- this.context = context;
- this.imgResId = R.drawable.icon_seekbar_day;
- }
-
- @Override
- protected void onSizeChanged(int w, int h, int oldw, int oldh) {
- super.onSizeChanged(w, h, oldw, oldh);
- //设置矩形 left top right bottom 左上右下点的值 按照标注计算得出
- backgroundRectF.set(7, 0, 37, h);
- colorRectF.set(12, 5, 32, h-5);
- imgValidHeight = h - 44;
- imgPos = h - 44; // 设置一个初始位置
- }
-
-
- @Override
- protected void onDraw(Canvas canvas) {
- super.onDraw(canvas);
- drawBackground(canvas);
- drawSection(canvas);
- drawImage(canvas);
- }
-
- /**
- * 画背景
- * @param canvas 画布
- */
- private void drawBackground(Canvas canvas) {
- backPaint.setStyle(Paint.Style.FILL);
- backPaint.setAntiAlias(true); //抗锯齿
- backPaint.setColor(Color.parseColor("#FFFFFF"));
- //画圆角矩形,15为圆角的角度
- canvas.drawRoundRect(backgroundRectF, 15, 15, backPaint);
- }
-
- /**
- * 画分段数据
- * @param canvas 画布
- */
- private void drawSection(Canvas canvas) {
- int[] colorArray = {
- Color.parseColor("#FF0000"), Color.parseColor("#FF0000"),
- Color.parseColor("#00FF00"), Color.parseColor("#00FF00"),
- Color.parseColor("#0000FF"), Color.parseColor("#0000FF")
- };
- float[] positionArray = {
- 0f, 0.2f,
- 0.2f, 0.6f,
- 0.6f, 1f
- };
- colorPaint.setStyle(Paint.Style.FILL);
- colorPaint.setAntiAlias(true);
-
- //指定渐变色方向x轴方向不变,沿y方向渐变,渐变范围为 颜色条高度
- colorPaint.setShader(new LinearGradient(0, 0, 0, colorRectF.bottom, colorArray, positionArray, Shader.TileMode.REPEAT));
- canvas.drawRoundRect(colorRectF,15, 15, colorPaint);
- }
-
- /**
- * 画图片
- * @param canvas 画布
- */
- private void drawImage(Canvas canvas) {
- Bitmap bitmap = initBitmap(imgResId);
- canvas.save();
- canvas.translate(0, 0);
- canvas.drawBitmap(bitmap, 0, imgPos, null);
- canvas.restore();
- }
-
- /**
- *
- * @param resId
- * @return
- */
- private Bitmap initBitmap(int resId) {
- Bitmap originalBmp = BitmapFactory.decodeResource(context.getResources(), resId);
- return Bitmap.createScaledBitmap(originalBmp, 44, 44, true);
- }
-
- /**
- * 更新view
- * @param total 总长度
- * @param rest 剩余长度
- * @param sections 分段数据
- */
- public void updateView(int total, int rest, List
sections) { - float percent = (1f * rest) / total;
- //防止溢出
- if(percent < 0){
- return;
- }
- imgPos = (int)(percent * imgValidHeight);
- invalidate();
- }
- }
updateView方法还有第三个参数,是用来传出颜色条不同段的颜色和百分比数据的。根据此数据来更新颜色条。这里需要根据业务不同自己实现,我这里就不写了。
大家可能看出来了,这个视图是用来展示导航中不同路段交通情况和当前车辆进度用的。自定义view中可以在构造方法中获取一些自定义属性,像背景条和颜色条的边距、圆角这些都可以定义到xml中,因为只适配一种屏幕尺寸所以也没有做多尺寸适配。以前也没有做过,这次记录下来。