Java tutorial
/* * Copyright (C) 2015 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package android.support.v4.widget; import android.graphics.drawable.Drawable; import android.os.Build; import android.support.annotation.DrawableRes; import android.support.annotation.IdRes; import android.support.annotation.NonNull; import android.support.annotation.Nullable; import android.support.annotation.StyleRes; import android.widget.TextView; /** * Helper for accessing features in {@link TextView} introduced after API level * 4 in a backwards compatible fashion. */ public final class TextViewCompat { // Hide constructor private TextViewCompat() { } interface TextViewCompatImpl { void setCompoundDrawablesRelative(@NonNull TextView textView, @Nullable Drawable start, @Nullable Drawable top, @Nullable Drawable end, @Nullable Drawable bottom); void setCompoundDrawablesRelativeWithIntrinsicBounds(@NonNull TextView textView, @Nullable Drawable start, @Nullable Drawable top, @Nullable Drawable end, @Nullable Drawable bottom); void setCompoundDrawablesRelativeWithIntrinsicBounds(@NonNull TextView textView, @DrawableRes int start, @DrawableRes int top, @DrawableRes int end, @DrawableRes int bottom); int getMaxLines(TextView textView); int getMinLines(TextView textView); void setTextAppearance(@NonNull TextView textView, @StyleRes int resId); } static class BaseTextViewCompatImpl implements TextViewCompatImpl { @Override public void setCompoundDrawablesRelative(@NonNull TextView textView, @Nullable Drawable start, @Nullable Drawable top, @Nullable Drawable end, @Nullable Drawable bottom) { textView.setCompoundDrawables(start, top, end, bottom); } @Override public void setCompoundDrawablesRelativeWithIntrinsicBounds(@NonNull TextView textView, @Nullable Drawable start, @Nullable Drawable top, @Nullable Drawable end, @Nullable Drawable bottom) { textView.setCompoundDrawablesWithIntrinsicBounds(start, top, end, bottom); } @Override public void setCompoundDrawablesRelativeWithIntrinsicBounds(@NonNull TextView textView, @DrawableRes int start, @DrawableRes int top, @DrawableRes int end, @DrawableRes int bottom) { textView.setCompoundDrawablesWithIntrinsicBounds(start, top, end, bottom); } @Override public int getMaxLines(TextView textView) { return TextViewCompatDonut.getMaxLines(textView); } @Override public int getMinLines(TextView textView) { return TextViewCompatDonut.getMinLines(textView); } @Override public void setTextAppearance(TextView textView, @StyleRes int resId) { TextViewCompatDonut.setTextAppearance(textView, resId); } } static class JbTextViewCompatImpl extends BaseTextViewCompatImpl { @Override public int getMaxLines(TextView textView) { return TextViewCompatJb.getMaxLines(textView); } @Override public int getMinLines(TextView textView) { return TextViewCompatJb.getMinLines(textView); } } static class JbMr1TextViewCompatImpl extends JbTextViewCompatImpl { @Override public void setCompoundDrawablesRelative(@NonNull TextView textView, @Nullable Drawable start, @Nullable Drawable top, @Nullable Drawable end, @Nullable Drawable bottom) { TextViewCompatJbMr1.setCompoundDrawablesRelative(textView, start, top, end, bottom); } @Override public void setCompoundDrawablesRelativeWithIntrinsicBounds(@NonNull TextView textView, @Nullable Drawable start, @Nullable Drawable top, @Nullable Drawable end, @Nullable Drawable bottom) { TextViewCompatJbMr1.setCompoundDrawablesRelativeWithIntrinsicBounds(textView, start, top, end, bottom); } @Override public void setCompoundDrawablesRelativeWithIntrinsicBounds(@NonNull TextView textView, @DrawableRes int start, @DrawableRes int top, @DrawableRes int end, @DrawableRes int bottom) { TextViewCompatJbMr1.setCompoundDrawablesRelativeWithIntrinsicBounds(textView, start, top, end, bottom); } } static class JbMr2TextViewCompatImpl extends JbMr1TextViewCompatImpl { @Override public void setCompoundDrawablesRelative(@NonNull TextView textView, @Nullable Drawable start, @Nullable Drawable top, @Nullable Drawable end, @Nullable Drawable bottom) { TextViewCompatJbMr2.setCompoundDrawablesRelative(textView, start, top, end, bottom); } @Override public void setCompoundDrawablesRelativeWithIntrinsicBounds(@NonNull TextView textView, @Nullable Drawable start, @Nullable Drawable top, @Nullable Drawable end, @Nullable Drawable bottom) { TextViewCompatJbMr2.setCompoundDrawablesRelativeWithIntrinsicBounds(textView, start, top, end, bottom); } @Override public void setCompoundDrawablesRelativeWithIntrinsicBounds(@NonNull TextView textView, @DrawableRes int start, @DrawableRes int top, @DrawableRes int end, @DrawableRes int bottom) { TextViewCompatJbMr2.setCompoundDrawablesRelativeWithIntrinsicBounds(textView, start, top, end, bottom); } } static class Api23TextViewCompatImpl extends JbMr2TextViewCompatImpl { @Override public void setTextAppearance(@NonNull TextView textView, @StyleRes int resId) { TextViewCompatApi23.setTextAppearance(textView, resId); } } static final TextViewCompatImpl IMPL; static { final int version = Build.VERSION.SDK_INT; if (version >= 23) { IMPL = new Api23TextViewCompatImpl(); } else if (version >= 18) { IMPL = new JbMr2TextViewCompatImpl(); } else if (version >= 17) { IMPL = new JbMr1TextViewCompatImpl(); } else if (version >= 16) { IMPL = new JbTextViewCompatImpl(); } else { IMPL = new BaseTextViewCompatImpl(); } } /** * Sets the Drawables (if any) to appear to the start of, above, to the end * of, and below the text. Use {@code null} if you do not want a Drawable * there. The Drawables must already have had {@link Drawable#setBounds} * called. * <p/> * Calling this method will overwrite any Drawables previously set using * {@link TextView#setCompoundDrawables} or related methods. * * @param textView The TextView against which to invoke the method. * @attr name android:drawableStart * @attr name android:drawableTop * @attr name android:drawableEnd * @attr name android:drawableBottom */ public static void setCompoundDrawablesRelative(@NonNull TextView textView, @Nullable Drawable start, @Nullable Drawable top, @Nullable Drawable end, @Nullable Drawable bottom) { IMPL.setCompoundDrawablesRelative(textView, start, top, end, bottom); } /** * Sets the Drawables (if any) to appear to the start of, above, to the end * of, and below the text. Use {@code null} if you do not want a Drawable * there. The Drawables' bounds will be set to their intrinsic bounds. * <p/> * Calling this method will overwrite any Drawables previously set using * {@link TextView#setCompoundDrawables} or related methods. * * @param textView The TextView against which to invoke the method. * @attr name android:drawableStart * @attr name android:drawableTop * @attr name android:drawableEnd * @attr name android:drawableBottom */ public static void setCompoundDrawablesRelativeWithIntrinsicBounds(@NonNull TextView textView, @Nullable Drawable start, @Nullable Drawable top, @Nullable Drawable end, @Nullable Drawable bottom) { IMPL.setCompoundDrawablesRelativeWithIntrinsicBounds(textView, start, top, end, bottom); } /** * Sets the Drawables (if any) to appear to the start of, above, to the end * of, and below the text. Use 0 if you do not want a Drawable there. The * Drawables' bounds will be set to their intrinsic bounds. * <p/> * Calling this method will overwrite any Drawables previously set using * {@link TextView#setCompoundDrawables} or related methods. * * @param textView The TextView against which to invoke the method. * @param start Resource identifier of the start Drawable. * @param top Resource identifier of the top Drawable. * @param end Resource identifier of the end Drawable. * @param bottom Resource identifier of the bottom Drawable. * @attr name android:drawableStart * @attr name android:drawableTop * @attr name android:drawableEnd * @attr name android:drawableBottom */ public static void setCompoundDrawablesRelativeWithIntrinsicBounds(@NonNull TextView textView, @DrawableRes int start, @DrawableRes int top, @DrawableRes int end, @DrawableRes int bottom) { IMPL.setCompoundDrawablesRelativeWithIntrinsicBounds(textView, start, top, end, bottom); } /** * Returns the maximum number of lines displayed in the given TextView, or -1 if the maximum * height was set in pixels instead. */ public static int getMaxLines(@NonNull TextView textView) { return IMPL.getMaxLines(textView); } /** * Returns the minimum number of lines displayed in the given TextView, or -1 if the minimum * height was set in pixels instead. */ public static int getMinLines(@NonNull TextView textView) { return IMPL.getMinLines(textView); } /** * Sets the text appearance from the specified style resource. * <p> * Use a framework-defined {@code TextAppearance} style like * {@link android.R.style#TextAppearance_Material_Body1 @android:style/TextAppearance.Material.Body1} * or see {@link android.R.styleable#TextAppearance TextAppearance} for the * set of attributes that can be used in a custom style. * * @param textView The TextView against which to invoke the method. * @param resId The resource identifier of the style to apply. */ public static void setTextAppearance(@NonNull TextView textView, @StyleRes int resId) { IMPL.setTextAppearance(textView, resId); } }