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關於Canvas和Paint的相關設定可以看這篇: Canvas/Paint 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 學習總集