Android开发之WebView输入框提示解决办法

做基于WebView应用时，页面上有一个输入框，当输入的文字过多时，超过输入框的行数时，输入框能够滚动，这时间问题来了，输入的提示箭头会移动到输入框外，如何解决这个问题呢，查找chromium源码如下：

void LoadIfNecessary(jobject context) {if (loaded_)return;loaded_ = true;TRACE_EVENT0("browser", "HandleResources::Create");JNIEnv* env = base::Android::AttachCurrentThread();if (!context)context = base::android::GetApplicationContext();left_bitmap_ = CreateSkBitmapFromJavaBitmap(Java_HandleViewResources_getLeftHandleBitmap(env, context));right_bitmap_ = CreateSkBitmapFromJavaBitmap(Java_HandleViewResources_getRightHandleBitmap(env, context));center_bitmap_ = CreateSkBitmapFromJavaBitmap(Java_HandleViewResources_getCenterHandleBitmap(env, context));left_bitmap_.setImmutable();right_bitmap_.setImmutable();center_bitmap_.setImmutable();drawable_horizontal_padding_ratio_ =Java_HandleViewResources_getHandleHorizontalPaddingRatio(env);}

这个函数加载这几个图片，在java端，

private static Bitmap getHandleBitmap(Context context, final int[] attrs) {// TODO(jdduke): Properly derive and apply theme color.TypedArray a = context.getTheme().obtainStyledAttributes(attrs);final int resId = a.getResourceId(a.getIndex(0), 0);final Resources res = a.getResources();a.recycle();final Bitmap.Config config = Bitmap.Config.ARGB_8888;final BitmapFactory.Options options = new BitmapFactory.Options();options.inJustDecodeBounds = false;options.inPreferredConfig = config;Bitmap bitmap = BitmapFactory.decodeResource(res, resId, options);savePic( bitmap);if (bitmap != null) return bitmap;// If themed resource lookup fails, fall back to using the Context's// resources for attribute lookup.if (res != context.getResources()) {bitmap = BitmapFactory.decodeResource(context.getResources(), resId, options);if (bitmap != null) return bitmap;}Drawable drawable = getHandleDrawable(context, attrs);assert drawable != null;final int width = drawable.getIntrinsicWidth();final int height = drawable.getIntrinsicHeight();Bitmap canvasBitmap = Bitmap.createBitmap(width, height, config);Canvas canvas = new Canvas(canvasBitmap);drawable.setBounds(0, 0, width, height);drawable.draw(canvas);return canvasBitmap;}

C++中会调用java中的函数getHandleBitmap，这个函数通过 context.getTheme().obtainStyledAttributes 这个函数，从jdk中加载图片资源，显示时，通过GetBitmap函数获取到图像信息，通过layer_->SetBitmap( bitmap)设置显示的内容，函数如下：

const SkBitmap& GetBitmap(ui::TouchHandleOrientation orientation) {DCHECK(loaded_);switch (orientation) {case ui::TouchHandleOrientation::LEFT:return left_bitmap_;case ui::TouchHandleOrientation::RIGHT:return right_bitmap_;case ui::TouchHandleOrientation::CENTER:return center_bitmap_;case ui::TouchHandleOrientation::UNDEFINED:NOTREACHED() << "Invalid touch handle orientation.";};return center_bitmap_;}

这么分析下来，想从显示下手解决这个问题，似乎不太可能，那只有替换图片资源，而图像资源是在android.jar包中，还有其他办法吗？ 分析源码，

public static Drawable getLeftHandleDrawable(Context context) {return getHandleDrawable(context, LEFT_HANDLE_ATTRS);}public static Drawable getCenterHandleDrawable(Context context) {return getHandleDrawable(context, CENTER_HANDLE_ATTRS);}public static Drawable getRightHandleDrawable(Context context) {return getHandleDrawable(context, RIGHT_HANDLE_ATTRS);}

有这几个图像id 信息，是不是可以重载呢，于是添加自己的

<?xml version="1.0" encoding="utf-8"?><resources><style name="MyTheme"><item name="android:textSelectHandleLeft">@drawable/ic_launcher</item><item name="android:textSelectHandle">@drawable/aa</item><item name="android:textSelectHandleRight">@drawable/ic_launcher</item></style></resources>

替换掉系统的资源，再添加android:theme=”@style/MyTheme” 自己的主题风格，问题解决

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