Android自定义控件-下载进度条

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Android自定义控件-下载进度条

效果展示

源码

• 布局

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <TextView
        android:id="@+id/tv_progress"
        android:textColor="#f00"
        android:textSize="15sp"
        android:text="下载进度："
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <...DownLoadProgressbar
        android:layout_centerHorizontal="true"
        android:layout_below="@id/tv_progress"
        android:id="@+id/dlp_current"
        android:layout_marginTop="20dp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
    <Button
        android:layout_marginTop="100dp"
        android:layout_below="@id/tv_progress"
        android:onClick="start"
        android:text="开始"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
</RelativeLayout>

• 控件

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;
import android.view.ViewTreeObserver;

import com.blankj.utilcode.util.SizeUtils;

/**
 * 进度条
 */
public class DownLoadProgressbar extends View {
    private Paint paint = new Paint(); // 绘制背景灰色线条画笔
    private Paint paintText = new Paint(); // 绘制下载进度画笔
    private float offset = 0f; // 下载偏移量
    private float maxvalue = 0f; // 进度的总大小
    private float currentValue = 0f; // 当前进度
    private Rect mBound = new Rect(); // 获取百分比数字的长宽
    private String percentValue = "0%"; // 要显示的现在百分比
    private float offsetRight = 0f; // 灰色线条距离右边的距离
    private int textSize = SizeUtils.sp2px(25); // 百分比的文字大小
    private float offsetTop = SizeUtils.dp2px(18); // 距离顶部的偏移量


    public DownLoadProgressbar(Context context) {
        this(context, null);
    }

    public DownLoadProgressbar(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public DownLoadProgressbar(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        getTextWidth();
    }


    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        // 绘制底色
        paint.setColor(Color.parseColor("#cccccc"));
        paint.setStrokeWidth(SizeUtils.dp2px(1));
        canvas.drawLine(0, offsetTop, getWidth(), offsetTop, paint);
        // 绘制进度条颜色
        paint.setColor(Color.parseColor("#ff0000"));
        paint.setStrokeWidth(SizeUtils.dp2px(2));
        canvas.drawLine(0, offsetTop, offset, offsetTop, paint);
        paint.setColor(Color.parseColor("#ffffff"));
        paint.setStrokeWidth(SizeUtils.dp2px(1));
        paintText.setColor(Color.parseColor("#ff0000"));
        paintText.setTextSize(textSize);
        paintText.setAntiAlias(true);
        paintText.getTextBounds(percentValue, 0, percentValue.length(), mBound);
        canvas.drawLine(offset, offsetTop, offset + mBound.width() + SizeUtils.dp2px(4), offsetTop, paint);
        canvas.drawText(percentValue, offset, offsetTop + mBound.height() / 2 - SizeUtils.dp2px(2), paintText);
    }

    public void setCurrentValue(float currentValue) {
        this.currentValue = currentValue;
        int value = (int) (currentValue * 100 / maxvalue);
        if (value < 100 && value > 0) {
            percentValue = value + "%";
        } else if (value <= 0) {
            percentValue = "0%";
        } else {
            percentValue = "100%";
        }
        calc();
        invalidate();
    }


    private void calc() {
        if (currentValue < maxvalue) {
            offset = (getWidth() - offsetRight) * currentValue / maxvalue;
        } else {
            offset = getWidth() - offsetRight;
        }
    }

    /**
     * 设置最大值
     *
     * @param maxValue
     */
    public void setMaxvalue(int maxValue) {
        this.maxvalue = maxValue;
    }

    /**
     * 获取“100%”的宽度
     */
    public void getTextWidth() {
        Paint paint = new Paint();
        Rect rect = new Rect();
        paint.setTextSize(textSize);
        paint.setAntiAlias(true);
        paint.getTextBounds("100%", 0, "100%".length(), rect);
        offsetRight = rect.width() + SizeUtils.dp2px(5);;
    }
}

• Activity

import android.content.Context;
import android.content.Intent;
import android.os.Handler;
import android.os.Looper;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;

import ...R;

public class DownLoadProgressbarActivity extends AppCompatActivity {
   private Handler mHandler = new Handler(Looper.getMainLooper());
   private int current = 0;
   private int max = 100;
   private DownLoadProgressbar dlp_current;
   private TextView tv_progress;

   @Override
   protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.activity_down_load_progressbar);
       dlp_current = findViewById(R.id.dlp_current);
       tv_progress = findViewById(R.id.tv_progress);
       dlp_current.setMaxvalue(max);
   }

   public static void start(Context context) {
       context.startActivity(new Intent(context, DownLoadProgressbarActivity.class));
   }

   public void start(final View view) {
       if (current <= max) {
           dlp_current.setCurrentValue(current);
           mHandler.postDelayed(new Runnable() {
               @Override
               public void run() {
                   current++;
                   tv_progress.setText("下载进度：" + current + "/" + max);
                   start(view);
               }
           }, 100);
       } else {
           current = 100;
           tv_progress.setText("下载进度：" + current + "/" + max);
           mHandler.removeCallbacksAndMessages(null);
           current = 0;
       }
   }
}