WebKit之WebView输入框提示

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