Android TV上下翻屏

效果

初始化頁面，用戶將光標移動到BUTTON3上，並向上移動焦點。就切換屏幕，下圖：

控件類ScrollLinearLayout

繼承LinearLayout，ScrollLinearLayout.java代碼如下：

import android.content.Context;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.widget.LinearLayout;
import android.widget.Scroller;

public class ScrollLinearLayout extends LinearLayout {

    private Scroller scroller;

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

    public ScrollLinearLayout(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        scroller = new Scroller(context);
    }

    public void startScroll(int y) {
        scroller.startScroll(0, getScrollY(), 0, y);
        invalidate();
    }

    @Override
    public void computeScroll() {
        //判斷是否滾動完成
        if (scroller.computeScrollOffset()) {
            scrollTo(scroller.getCurrX(), scroller.getCurrY());
        }
    }
}

ScrollLinearLayoutActivity代碼

ScrollLinearLayoutActivity.java代碼如下：

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.KeyEvent;
import android.widget.Button;

import com.cc.demo.R;


public class ScrollLinearLayoutActivity extends AppCompatActivity {

    private ScrollLinearLayout scrollLinearLayout;
    private Button btn2;
    private Button btn3;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_scroll_linear_layout);
        //按照720P的絕對值佈局進行測試的。
        scrollLinearLayout = (ScrollLinearLayout) findViewById(R.id.svg);
        btn2 = (Button) findViewById(R.id.btn2);
        btn3 = (Button) findViewById(R.id.btn3);
        btn3.requestFocus();
    }

    @Override
    public boolean dispatchKeyEvent(KeyEvent event) {
        if (event.getAction() == KeyEvent.ACTION_DOWN) {
            switch (event.getKeyCode()) {
                case KeyEvent.KEYCODE_DPAD_UP:
                    if (btn3.isFocused()) {
                        scrollLinearLayout.startScroll(-600);
                    }
                    break;
                case KeyEvent.KEYCODE_DPAD_DOWN:
                    if (btn2.isFocused()) {
                        scrollLinearLayout.startScroll(600);
                    }
                    break;
            }
        }
        return super.dispatchKeyEvent(event);
    }

}

activity_scroll_linear_layout代碼

activity_scroll_linear_layout.xml 代碼如下：

<?xml version="1.0" encoding="utf-8"?>
<com.cc.demo.scroll.ScrollLinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/svg"
    android:layout_width="match_parent"
    android:layout_height="1320px"
    android:layout_marginTop="-600px"
    android:orientation="vertical">

    <Button
        android:id="@+id/btn1"
        android:layout_width="match_parent"
        android:layout_height="100px"
        android:text="button1"
        android:textColor="@color/white"
        android:textSize="20sp" />

    <Button
        android:id="@+id/btn2"
        android:layout_width="match_parent"
        android:layout_height="100px"
        android:text="button2"
        android:textColor="@color/white"
        android:textSize="20sp" />

    <View
        android:layout_width="match_parent"
        android:layout_height="400px"
        android:background="@color/colorPrimaryDark" />

    <Button
        android:id="@+id/btn3"
        android:layout_width="match_parent"
        android:layout_height="100px"
        android:layout_marginBottom="10dp"
        android:text="button3"
        android:textColor="@color/white"
        android:textSize="20sp" />

    <Button
        android:id="@+id/btn4"
        android:layout_width="match_parent"
        android:layout_height="100px"
        android:layout_marginBottom="10dp"
        android:text="button4"
        android:textColor="@color/white"
        android:textSize="20sp" />

    <Button
        android:id="@+id/btn5"
        android:layout_width="match_parent"
        android:layout_height="200px"
        android:layout_marginBottom="10dp"
        android:text="button5"
        android:textColor="@color/white"
        android:textSize="20sp" />

    <Button
        android:id="@+id/btn6"
        android:layout_width="match_parent"
        android:layout_height="200px"
        android:layout_marginBottom="10dp"
        android:text="button6"
        android:textColor="@color/white"
        android:textSize="20sp" />
</com.cc.demo.scroll.ScrollLinearLayout>

其它

• 根據具體的需求，TV上翻屏也可以用ScrollView來實現。
• Android TV上的ScrollView和HorizontalScrollView是可以直接使用。和觸摸屏上一樣。
• Android TV上也可以正常使用RecyclerView，焦點可能會存在小問題，上拉加載更多和下拉刷新需要自己實現。建議使用開源庫TvRecyclerView。