Android中将布局文件转成bitmap

在实践中发现，有些需要打印的小票高度小于屏幕的高度，而有些小票内容过多高度高于屏幕高度。

小于屏幕高度的布局文件转成bitmap较为容易，高于屏幕高度的布局文件转成长图bitmap较为复杂。

一.小于屏幕高度的布局文件转成bitmap

1.需求

在交易过程中常常需要打印小票，利用布局文件组织小票格式，并将其转成bitmap之后打印出来较为方便。

2.布局文件转bitmap

public class ReceiptViewActivity extends Activity{
    private View view;
    private boolean isEnd = false;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        LayoutInflater layoutInflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        view = layoutInflater.inflate(R.layout.activity_receiptview, null);
        setContentView(view);

        new Thread(new Runnable() {
            @Override
            public void run() {
                while (!isEnd){
                    try {
                        view.buildDrawingCache();
                        Bitmap bitmap = Bitmap.createBitmap(view.getDrawingCache());
                        Pic pic = new Pic(bitmap);
                        Printer printer = new Printer(SaleActivity.dal);
                        int printstatus = printer.printbitmap(pic);
                        if (printstatus == 0){
                            isEnd = true;
                        }
                    }catch (Exception e){
                        e.printStackTrace();
                    }
                }
            }
        }).start();
    }
}

二.高于屏幕高度的布局文件转成bitmap

1.需求

有时小票内容过多，屏幕显示不下，需要滚动显示并打印完整小票。

2.利用ScrlooView实现滚动显示

<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal"
    android:background="@color/white"
    android:orientation="vertical"
    android:scrollbars="none"
    android:id="@+id/scrollview">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:orientation="vertical">
        <TextView
            android:id="@+id/counter"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="@dimen/greater_magrin_space"
            android:gravity="center"
            android:text="10s"
            android:textColor="@color/black"
            android:textSize="@dimen/content_text_size_standard"/>
        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="@dimen/greater_magrin_space"
            android:gravity="center"
            android:text="@string/title_sale"
            android:textColor="@color/black"
            android:textSize="@dimen/content_text_size_standard"/>
        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="@dimen/content_header_space"
            android:gravity="center"
            android:text="@string/processing"
            android:textColor="@color/black"
            android:textSize="@dimen/content_text_size_standard"/>
        <TextView
            android:layout_width="match_parent"
            android:layout_height="@dimen/greater_magrin_space" />
        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="@dimen/greater_magrin_space"
            android:gravity="center"
            android:text="10s"
            android:textColor="@color/black"
            android:textSize="@dimen/content_text_size_standard"/>

    </LinearLayout>

</ScrollView>

3.布局文件转bitmap

public class ReceiptViewActivity extends Activity{
    private ScrollView scrollView;
    private boolean isEnd = false;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_receiptview);

        scrollView = (ScrollView)findViewById(R.id.scrollview);

        new Thread(new Runnable() {
            @Override
            public void run() {
                while (!isEnd){
                    try {
                        Bitmap bitmap = getBitmapByView(scrollView);
                        Pic pic = new Pic(bitmap);
                        Printer printer = new Printer(SaleActivity.dal);
                        int printstatus = printer.printbitmap(pic);
                        if (printstatus == 0){
                            isEnd = true;
                        }
                    }catch (Exception e){
                        e.printStackTrace();
                    }
                }
            }
        }).start();
    }
　　//ScrollView 转成bitmap长图
    public static Bitmap getBitmapByView(ScrollView scrollView) {
        int h = 0;
        Bitmap bitmap = null;

        for (int i = 0; i < scrollView.getChildCount(); i++) {
            h += scrollView.getChildAt(i).getHeight();
            scrollView.getChildAt(i).setBackgroundColor(
                    Color.parseColor("#ffffff"));
        }

        bitmap = Bitmap.createBitmap(scrollView.getWidth(), h,
                Bitmap.Config.RGB_565);
        final Canvas canvas = new Canvas(bitmap);
        scrollView.draw(canvas);
        return bitmap;
    }
}