Android ProgressBar 自定义样式（七），仿真QQ聊天、网易新闻客户端加载图片Loading

先上图，有图有真相：

   

其实也很简单，也是用了一下投机取巧的方法，大家有更多的方法的话，可以和我交流一下。

xml布局文件如下：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center"
    android:gravity="center" >

    <com.freesonfish.progress_bar.MyProgressBar4
        android:id="@+id/my_progress_bar_4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
         />

</LinearLayout>

自定义的View如下：

package com.freesonfish.progress_bar;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.Shader;
import android.graphics.SweepGradient;
import android.util.AttributeSet;
import android.view.View;

public class MyProgressBar4 extends View {

	private Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
	private Shader mShader;
	private float x = 50.0f, y = 50.0f;
	private float swap = 0.02f;
	private Matrix mMatrix = new Matrix();

	private Paint tPaint = new Paint();
	private String value = "";
	private Rect rect = new Rect();
	

	public MyProgressBar4(Context context, AttributeSet attr) {
		super(context, attr);
		initPaint();
	}

	public MyProgressBar4(Context context) {
		super(context);
		initPaint();
	}

	private void initPaint() {
		mShader = new SweepGradient(x, y, new int[] { 0xFFFF0000, 0xCCCCCCCC }, new float[] { 1.0f, swap });
		mMatrix.setRotate(-90, x, y);
		mShader.setLocalMatrix(mMatrix);
		mPaint.setShader(mShader);
		mPaint.setStyle(Paint.Style.STROKE);
		mPaint.setStrokeWidth(7);
		mPaint.setAntiAlias(true);

		tPaint.setColor(Color.GREEN);
		tPaint.setTextSize(16);
	}

	private void resetShader() {
		mShader = new SweepGradient(x, y, new int[] { 0xFFFF0000, 0xCCCCCCCC }, new float[] { 1.0f, swap });
		mShader.setLocalMatrix(mMatrix);
		mPaint.setShader(mShader);
	}

	@Override
	protected void onDraw(Canvas canvas) {
		Paint paint = mPaint;
		canvas.drawText(value, x - rect.centerX(), y - rect.centerY(), tPaint);
		canvas.drawCircle(x, y, 30, paint);
	}

	public void changeProgressValue() {
		swap += 0.08f;
		int swapValue = (int)(swap * 100f);
		value = (swapValue > 100 ? 100 : swapValue) + "%";
		tPaint.getTextBounds(value, 0, value.length(), rect);
		resetShader();
		invalidate();
	}

	public float getSwapValue() {
		return swap;
	}

}

测试Activity类如下：

package com.freesonfish.progress_bar;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;

import com.freesonfish.R;

public class MyprogressBarActivity4 extends Activity {

	MyProgressBar4 progressBar = null;

	Handler handler = new Handler() {
		public void handleMessage(android.os.Message msg) {
			if (progressBar.getSwapValue() <= 1.0f) {
				progressBar.changeProgressValue();
				handler.sendEmptyMessageDelayed(0, 500);
			}
		};
	};

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.my_progress_bar_4);
		progressBar = (MyProgressBar4) findViewById(R.id.my_progress_bar_4);
		handler.sendEmptyMessageDelayed(0, 500);
	}

}

大家是不是觉得很简单啊，哈哈

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