Android控件TextProgressBar进度条上显文字

Android系统的进度条控件默认的设计的不是很周全，比如没有包含文字的显示，那么如何在Android进度条控件上显示文字呢? 来自Google内部的代码来了解下，主要使用的addView这样的方法通过覆盖一层Chronometer秒表控件来实现，整个代码如下

public class TextProgressBar extends RelativeLayout implements OnChronometerTickListener { public static final String TAG = "TextProgressBar"; static final int CHRONOMETER_ID = android.R.id.text1; static final int PROGRESSBAR_ID = android.R.id.progress; Chronometer mChronometer = null; ProgressBar mProgressBar = null; long mDurationBase = -1; int mDuration = -1; boolean mChronometerFollow = false; int mChronometerGravity = Gravity.NO_GRAVITY; public TextProgressBar(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); } public TextProgressBar(Context context, AttributeSet attrs) { super(context, attrs); } public TextProgressBar(Context context) { super(context); } //Android开发网提示关键部分在这里 @Override public void addView(View child, int index, ViewGroup.LayoutParams params) { super.addView(child, index, params); int childId = child.getId(); if (childId == CHRONOMETER_ID && child instanceof Chronometer) { mChronometer = (Chronometer) child; mChronometer.setOnChronometerTickListener(this); // Check if Chronometer should move with with ProgressBar mChronometerFollow = (params.width == ViewGroup.LayoutParams.WRAP_CONTENT); mChronometerGravity = (mChronometer.getGravity() & Gravity.HORIZONTAL_GRAVITY_MASK); } else if (childId == PROGRESSBAR_ID && child instanceof ProgressBar) { mProgressBar = (ProgressBar) child; } } @android.view.RemotableViewMethod public void setDurationBase(long durationBase) { mDurationBase = durationBase; if (mProgressBar == null || mChronometer == null) { throw new RuntimeException("Expecting child ProgressBar with id " + "'android.R.id.progress' and Chronometer id 'android.R.id.text1'"); } // Update the ProgressBar maximum relative to Chronometer base mDuration = (int) (durationBase - mChronometer.getBase()); if (mDuration <= 0) { mDuration = 1; } mProgressBar.setMax(mDuration); } public void onChronometerTick(Chronometer chronometer) { if (mProgressBar == null) { throw new RuntimeException( "Expecting child ProgressBar with id 'android.R.id.progress'"); } // Stop Chronometer if we're past duration long now = SystemClock.elapsedRealtime(); if (now >= mDurationBase) { mChronometer.stop(); } int remaining = (int) (mDurationBase - now); mProgressBar.setProgress(mDuration - remaining); if (mChronometerFollow) { RelativeLayout.LayoutParams params; params = (RelativeLayout.LayoutParams) mProgressBar.getLayoutParams(); int contentWidth = mProgressBar.getWidth() - (params.leftMargin + params.rightMargin); int leadingEdge = ((contentWidth * mProgressBar.getProgress()) / mProgressBar.getMax()) + params.leftMargin; int adjustLeft = 0; int textWidth = mChronometer.getWidth(); if (mChronometerGravity == Gravity.RIGHT) { adjustLeft = -textWidth; } else if (mChronometerGravity == Gravity.CENTER_HORIZONTAL) { adjustLeft = -(textWidth / 2); } leadingEdge += adjustLeft; int rightLimit = contentWidth - params.rightMargin - textWidth; if (leadingEdge < params.leftMargin) { leadingEdge = params.leftMargin; } else if (leadingEdge > rightLimit) { leadingEdge = rightLimit; } params = (RelativeLayout.LayoutParams) mChronometer.getLayoutParams(); params.leftMargin = leadingEdge; mChronometer.requestLayout(); } }}