如何在Android所有界面上实现水印

来源：互联网发布：xquartz2.7.9 mac 编辑：程序博客网时间：2024/06/06 06:35

在一些对安全性要求较高的app中,会要求对所有的界面加上水印,防止截屏泄露客户信息,总体思路是获取底层的布局,在布局上add一个自定义的水印View,由于添加View必须要在setContentView之后,所以把添加水印的过程放在onStart中,并加上判断防止多次添加.

自定义水印布局

注:RotateTextView布局转自http://download.csdn.net/download/fangjxl/9485001

<?xml version="1.0" encoding="utf-8"?><FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:app="http://schemas.android.com/apk/res-auto"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical"     android:background="#00000000"><LinearLayout     android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical">   <LinearLayout        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_marginTop="40dp"        android:orientation="horizontal" >        <RotateTextView            android:id="@+id/fragment_tag11"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_gravity="left"            android:layout_marginLeft="20dp"            android:text="@string/app_name"            android:textColor="#22666666"            android:textSize="22sp"            app:degree="350dp" />        <RotateTextView            android:id="@+id/fragment_tag12"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_gravity="center_horizontal"            android:layout_marginLeft="20dp"            android:text="@string/app_name"            android:textColor="#22666666"            android:textSize="22sp"            app:degree="350dp" />        <RotateTextView            android:id="@+id/fragment_tag13"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_gravity="right"            android:layout_marginLeft="20dp"            android:text="@string/app_name"            android:textColor="#22666666"            android:textSize="22sp"            app:degree="350dp" />        <RotateTextView            android:id="@+id/fragment_tag14"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_gravity="right"            android:layout_marginLeft="20dp"            android:text="@string/app_name"            android:textColor="#22666666"            android:textSize="22sp"            app:degree="350dp" />    </LinearLayout></LinearLayout></FrameLayout>

attr

    <declare-styleable name="RotateTextView">        <attr name="degree" format="dimension" />    </declare-styleable>

java

RotateTextView

public class RotateTextView extends TextView {    @Override    public void setText(CharSequence text, BufferType type) {        // TODO Auto-generated method stub        super.setText(waterMark, type);    }    private static final int DEFAULT_DEGREES = 0;    //水印文字    public static String waterMark = "";    private int mDegrees;    public RotateTextView(Context context) {        super(context, null);    }    public RotateTextView(Context context, AttributeSet attrs) {        super(context, attrs, android.R.attr.textViewStyle);        this.setGravity(Gravity.CENTER);        TypedArray a = context.obtainStyledAttributes(attrs,                R.styleable.RotateTextView);        mDegrees = a.getDimensionPixelSize(R.styleable.RotateTextView_degree,                DEFAULT_DEGREES);        a.recycle();    }    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {        super.onMeasure(widthMeasureSpec, heightMeasureSpec);        setMeasuredDimension(getMeasuredWidth(), getMeasuredWidth());    }    @Override    protected void onDraw(Canvas canvas) {        canvas.save();        canvas.translate(getCompoundPaddingLeft(), getExtendedPaddingTop());        canvas.rotate(mDegrees, this.getWidth() / 2f, this.getHeight() / 2f);        super.onDraw(canvas);        canvas.restore();    }    public void setDegrees(int degrees) {        mDegrees = degrees;    }}

Activity

    @Override    protected void onStart() {    //判断是否已经添加过        if(isAdd){        }else {            ViewGroup rootView = getRootView(this);            View framView = LayoutInflater.from(this).inflate(R.layout.fragment_layout, null);            rootView.addView(framView);            isAdd=true;        }        super.onStart();    }    //查找布局的底层    protected static ViewGroup getRootView(Activity context)      {          return (ViewGroup)context.findViewById(android.R.id.content);      }

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