使用进度条控制画布控件缩放

- 移除顶部放大/缩小按钮，改用底部SeekBar进度条控制
- 缩放范围0.1-5.0对应进度条0-100
- 添加setScaleFactor()方法

gallery/src/main/java/cc/winboll/studio/gallery/CropActivity.java

@@ -10,6 +10,7 @@ import android.provider.MediaStore;
 import android.view.View;
 import android.widget.ImageView;
 import android.widget.ScrollView;
+import android.widget.SeekBar;
 import android.widget.Toast;
 import androidx.appcompat.app.AppCompatActivity;
 import cc.winboll.studio.libappbase.LogUtils;
@@ -78,22 +79,22 @@ public class CropActivity extends AppCompatActivity {
         });
         
         zoomContainer = findViewById(R.id.zoom_container);
-        findViewById(R.id.btn_zoom_in).setOnClickListener(new View.OnClickListener() {
-            @Override
-            public void onClick(View v) {
-                if (zoomContainer != null) {
-                    zoomContainer.zoomIn();
-                }
-            }
-        });
         
-        findViewById(R.id.btn_zoom_out).setOnClickListener(new View.OnClickListener() {
+        SeekBar seekBarZoom = findViewById(R.id.seekbar_zoom);
+        seekBarZoom.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
             @Override
-            public void onClick(View v) {
-                if (zoomContainer != null) {
-                    zoomContainer.zoomOut();
+            public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
+                if (zoomContainer != null && fromUser) {
+                    float scale = 0.1f + (progress / 100f) * 4.9f;
+                    zoomContainer.setScaleFactor(scale);
                 }
             }
+            
+            @Override
+            public void onStartTrackingTouch(SeekBar seekBar) {}
+            
+            @Override
+            public void onStopTrackingTouch(SeekBar seekBar) {}
         });
         
         cropCanvasView = findViewById(R.id.crop_canvas_view);

gallery/src/main/java/cc/winboll/studio/gallery/ZoomContainerView.java

@@ -13,7 +13,7 @@ import android.widget.FrameLayout;
 
 public class ZoomContainerView extends FrameLayout {
     private float scaleFactor = 1.0f;
-    private float minScale = 0.5f;
+    private float minScale = 0.1f;
     private float maxScale = 5.0f;
     private static final float ZOOM_STEP = 0.25f;
     
@@ -98,6 +98,12 @@ public class ZoomContainerView extends FrameLayout {
         return scaleFactor;
     }
     
+    public void setScaleFactor(float scale) {
+        scaleFactor = Math.max(minScale, Math.min(scale, maxScale));
+        requestLayout();
+        invalidate();
+    }
+    
     public void resetZoom() {
         scaleFactor = 1.0f;
         invalidate();