關於Canvas和Paint的相關設定可以看這篇:
示範
XML
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<Button
android:id="@+id/b1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="bitmap"
android:text="Bitmap"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<ImageView
android:id="@+id/ig1"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintBottom_toTopOf="@+id/b1"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.502"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>
JAVA
public class MainActivity extends AppCompatActivity {
Bitmap bitmap;
ImageView ig1;
Canvas canvas;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ig1=(ImageView)findViewById(R.id.ig1);
}
public void bitmap(View v){
bitmap=Bitmap.createBitmap(ig1.getWidth(),ig1.getHeight(),Bitmap.Config.ARGB_8888);//創建Bitmap畫布
Paint paint = new Paint();//創建畫筆
paint.setColor(Color.BLACK);//設置畫筆顏色
paint.setStyle(Paint.Style.FILL);//設置中空或是填滿畫筆
paint.setTextSize(100);//設置文字顏色
canvas = new Canvas(bitmap);
canvas.drawCircle(ig1.getWidth()/2, ig1.getHeight()/2, 400, paint);//繪製圓形(寬/高/元半徑/選擇畫筆)
ig1.setImageBitmap(bitmap);//將Bitmap圖片載入ImageView元件
}
}
展示
相關文章:
[Android] Android 程式設計教學
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