安卓自定义一个水平进度条，根据后台返回的数据显示进度，详细源码

好的，下面是一个简单的自定义水平进度条的代码实现，根据后台返回的数据显示进度：

1. 首先，在res/layout文件夹下新建一个xml文件，例如progress_bar_horizontal.xml，添加如下代码：

<com.example.myapplication.HorizontalProgressBar
    android:id="@+id/progress_bar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:max="100"
    app:progress="0"
    app:progress_color="@color/colorAccent"
    app:secondary_progress_color="@color/colorPrimary"
    app:background_color="@color/colorGray"
    app:text_color="@color/colorBlack"
    app:text_size="14sp"
    app:text_visible="true" />

其中，自定义的HorizontalProgressBar组件继承自ProgressBar，所以在xml中使用时需要写全类名。

2. 在res/values文件夹下新建一个attrs.xml文件，添加自定义属性：

<resources>
    <declare-styleable name="HorizontalProgressBar">
        <attr name="progress_color" format="color" />
        <attr name="secondary_progress_color" format="color" />
        <attr name="background_color" format="color" />
        <attr name="text_color" format="color" />
        <attr name="text_size" format="dimension" />
        <attr name="text_visible" format="boolean" />
        <attr name="max" format="integer" />
        <attr name="progress" format="integer" />
    </declare-styleable>
</resources>

3. 新建一个HorizontalProgressBar.java文件，添加如下代码：

public class HorizontalProgressBar extends ProgressBar {
 
    private int mTextColor;
    private float mTextSize;
    private boolean mTextVisible;
 
    private int mProgressColor;
    private int mSecondaryProgressColor;
    private int mBackgroundColor;
 
    private Paint mPaint;
    private Rect mRect;
 
    public HorizontalProgressBar(Context context) {
        super(context);
        init(null);
    }
 
    public HorizontalProgressBar(Context context, AttributeSet attrs) {
        super(context, attrs);
        init(attrs);
    }
 
    public HorizontalProgressBar(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        init(attrs);
    }
 
    @Override
    protected synchronized void onDraw(Canvas canvas) {
        super.onDraw(canvas);
 
        // 绘制背景
        mPaint.setColor(mBackgroundColor);
        canvas.drawRect(mRect, mPaint);
 
        // 绘制进度
        float progressRatio = (float)getProgress() / (float)getMax();
        int progressWidth = (int)(progressRatio * getWidth());
        mPaint.setColor(mProgressColor);
        canvas.drawRect(0, 0, progressWidth, getHeight(), mPaint);
 
        // 绘制次进度
        float secondaryProgressRatio = (float)getSecondaryProgress() / (float)getMax();
        int secondaryProgressWidth = (int)(secondaryProgressRatio * getWidth());
        mPaint.setColor(mSecondaryProgressColor);
        canvas.drawRect(0, 0, secondaryProgressWidth, getHeight(), mPaint);
 
        // 绘制文字
        if (mTextVisible) {
            mPaint.setColor(mTextColor);
            mPaint.setTextSize(mTextSize);
            String progressText = getProgress() + "%";
            float textWidth = mPaint.measureText(progressText);
            float textX = (getWidth() - textWidth) / 2;
            float textY = (getHeight() + mTextSize) / 2 - mPaint.descent();
            canvas.drawText(progressText, textX, textY, mPaint);
        }
    }
 
    private void init(AttributeSet attrs) {
        // 初始化属性
        if (attrs != null) {
            TypedArray ta = getContext().obtainStyledAttributes(attrs, R.styleable.HorizontalProgressBar);
            mTextColor = ta.getColor(R.styleable.HorizontalProgressBar_text_color, Color.BLACK);
            mTextSize = ta.getDimension(R.styleable.HorizontalProgressBar_text_size, 14);
            mTextVisible = ta.getBoolean(R.styleable.HorizontalProgressBar_text_visible, true);
            mProgressColor = ta.getColor(R.styleable.HorizontalProgressBar_progress_color, Color.BLUE);
            mSecondaryProgressColor = ta.getColor(R.styleable.HorizontalProgressBar_secondary_progress_color, Color.GRAY);
            mBackgroundColor = ta.getColor(R.styleable.HorizontalProgressBar_background_color, Color.TRANSPARENT);
            ta.recycle();
        } else {
            mTextColor = Color.BLACK;
            mTextSize = 14;
            mTextVisible = true;
            mProgressColor = Color.BLUE;
            mSecondaryProgressColor = Color.GRAY;
            mBackgroundColor = Color.TRANSPARENT;
        }
 
        // 初始化画笔
        mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mRect = new Rect(0, 0, getWidth(), getHeight());
    }
}

4. 在Activity中获取ProgressBar组件，并根据后台返回的数据设置进度，例如：

HorizontalProgressBar progressBar = findViewById(R.id.progress_bar);
int progress = (int)(data/current * 100); // data为当前值，current为总值
progressBar.setProgress(progress);

这样就完成了自定义水平进度条的实现。