Android TV 焦点框移动

 Tv开发，最重要的当然是焦点框的移动，有了焦点框我们才能知道当前选中的是哪一个，我们来看下效果图：

焦点框移动

那它是怎么实现的呢，我们一起来看下。

原理

布局上使用一个view，背景是.9图片做焦点框，选中一个控件的时候把这个view移动选中的控件的位置。怎么样，是不是很简单，行动起来。先看下布局

codeing

布局：

最底下的View就是我们要用到的焦点框

代码

import android.app.Activity;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.FrameLayout;

public class MainActivity extends Activity implements View.OnFocusChangeListener{

    private String TAG ="qkmin";
    private int Layout1 = R.id.id_fl;
    private int Layout2 = R.id.id_fl_2;
    private View onFousView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        initViews();

    }

    private void initViews() {
        FrameLayout frameLayout=findViewById(Layout1);
        FrameLayout frameLayout2=findViewById(Layout2);
        onFousView = findViewById(R.id.id_focus);
        //设置焦点变化监听
        frameLayout.setOnFocusChangeListener(this);
        frameLayout2.setOnFocusChangeListener(this);
    }

    @Override
    public void onFocusChange(View v, boolean hasFocus) {
        if (hasFocus){
            Log.i(TAG,"onFocusChange"+v.getId());
            //设置焦点框的位置和动画
            Tools.focusAnimator(v,onFousView);
        }
    }
}

我们来看下Tools 这个类：

import android.animation.Animator;
import android.animation.AnimatorSet;
import android.animation.ObjectAnimator;
import android.animation.ValueAnimator;
import android.view.View;
import android.view.ViewGroup;

public class Tools {

    private static int mFocusWidth;
    private static int mFoucsHeight;

    public static void focusAnimator(View v, View onFousView) {
        focusAnimator(v, onFousView, -1, 0, 0);
    }




    public static void focusAnimator(View parentView, final View focusView, int scrollY, int offSetX, int offSetY) {
        int[] fromLocation = new int[2];
        focusView.getLocationOnScreen(fromLocation);

        int fromWidth = focusView.getWidth();
        int fromHeight = focusView.getHeight();
        float fromX = fromLocation[0];
        float fromY = fromLocation[1];

        int[] toLocation = new int[2];
        parentView.getLocationOnScreen(toLocation);

        int toWidth = parentView.getWidth() + offSetX;
        int toHeight = parentView.getHeight() + offSetY;
        float toX = toLocation[0] - offSetX / 2;
        float toY = toLocation[1] - offSetY / 2;



        if (scrollY == -1) {
            if (focusView.getVisibility() == View.GONE)
                focusView.setVisibility(View.VISIBLE);
        }

        AnimatorSet animatorSet = new AnimatorSet();
        ObjectAnimator translateXAnimator = ObjectAnimator.ofFloat(focusView, "x", fromX, toX);
        translateXAnimator.addListener(new Animator.AnimatorListener() {

            @Override
            public void onAnimationStart(Animator animation) {
            }

            @Override
            public void onAnimationRepeat(Animator animation) {
            }

            @Override
            public void onAnimationEnd(Animator animation) {
                if (focusView.getVisibility() == View.GONE) {
                    focusView.setVisibility(View.VISIBLE);
                }
            }

            @Override
            public void onAnimationCancel(Animator animation) {
                if (focusView.getVisibility() == View.GONE)
                    focusView.setVisibility(View.VISIBLE);
            }
        });
        ObjectAnimator translateYAnimator = ObjectAnimator.ofFloat(focusView, "y", fromY, toY);
        ValueAnimator scaleWidthAnimator = ObjectAnimator.ofFloat(focusView, "width", fromWidth, toWidth);
        scaleWidthAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {

            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                float width = (Float) animation.getAnimatedValue();
                mFocusWidth = (int) width;
                ViewGroup.LayoutParams layoutParams = focusView.getLayoutParams();
                layoutParams.width = mFocusWidth;
                layoutParams.height = mFoucsHeight;
                focusView.setLayoutParams(layoutParams);
            }
        });
        ValueAnimator scaleHeightAnimator = ObjectAnimator.ofFloat(focusView, "height", fromHeight, toHeight);
        scaleHeightAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {

            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                float height = (Float) animation.getAnimatedValue();
                mFoucsHeight = (int) height;
                ViewGroup.LayoutParams layoutParams = focusView.getLayoutParams();
                layoutParams.width = mFocusWidth;
                layoutParams.height = mFoucsHeight;
                focusView.setLayoutParams(layoutParams);
            }
        });
        animatorSet.playTogether(translateXAnimator, translateYAnimator, scaleWidthAnimator, scaleHeightAnimator);
        animatorSet.setDuration(150);
        animatorSet.start();
    }

}

主要方法是focusAnimator（），首先获取focusView的宽、高，以及x ,y 坐标，在得到获取焦点的view的宽、高，以及x ,y 坐标，最会设置动画。这样就Ok了。
下面是项目地址
https://gitee.com/love_k/FocusTest.git