Android文本旋转:我使用dynamiclayout.draw(canvas)绘制文本,但它不能沿路径动画运动,并且无法使用canvas.drawTextOnPath(dynamiclayout)。

12

我正在使用自己修改版的https://github.com/mdg-iitr/RotatingText,以展示旋转文本小部件。该GitHub中提供了视频,可让您观看动画。思路是设置单词行。行逐行显示。整个行旋转(它的单词也旋转)。当后者的旋转动画结束时,下一行将显示在前一行之后。

我的问题

我使用DynamicLayout来显示文本行。记住:这些行必须旋转。

我的问题是:显然,我不能使用方法canvas.drawTextOnPath(dynamicLayoutObject)。因此,我所做的是: dynamicLayoutObjec.draw(canvas);。但是,那里没有任何动画。的确,文本(包含它的DynamicLayout)必须旋转。

期望结果

DynamicLayout(实际上,它的文本)必须进行动画处理(旋转)。旋转可以在开始SO问题时给出的Github原始存储库的插图中找到(https://github.com/mdg-iitr/RotatingText)。

我的问题

我不知道如何使我的DynamicLayout(和/或它的文本)沿着路径旋转。

最小且可测试的示例

我大约8个月前修改了原始的RotatingText库,以便简化它(更少的类、更少的方法、没有未使用的方法等)。实际上,我只有两个类:

  1. RotatingTextSwitcher,即XML小部件

  2. 和包含要旋转的字符串数组的Rotatable

  3. 一个包含XML小部件RotatingTextSwitcher的.XML布局,以便测试它

  4. 一个Fragment填充先前提到的布局,设置每个旋转行的单词,并显示它们。

要进行测试,请创建一个活动,展示以下给出的片段,该片段又使用了前面提到的其他资源。

Rotatable类

import android.graphics.Path;
import android.view.animation.Interpolator;

public class Rotatable {

    private final String[] text;
    private final int update_duration;
    private int animation_duration;
    private Path path_in, path_out;
    private int currentWordNumber;
    private Interpolator interpolator;

    public Rotatable(int update_duration, int animation_duration, Interpolator interpolator, String... text) {
        this.update_duration = update_duration;
        this.animation_duration = animation_duration;
        this.text = text;
        this.interpolator = interpolator;
        currentWordNumber = -1;
    }

    private int nextWordNumber() {
        currentWordNumber = (currentWordNumber + 1) % text.length;
        return currentWordNumber;
    }

    String nextWord() {
        return text[nextWordNumber()];
    }

    Path getPathIn() {
        return path_in;
    }
    void setPathIn(Path path_in) {
        this.path_in = path_in;
    }
    Path getPathOut() {
        return path_out;
    }
    void setPathOut(Path path_out) {
        this.path_out = path_out;
    }

    int getUpdateDuration() {
        return update_duration;
    }

    int getAnimationDuration() {
        return animation_duration;
    }

    Interpolator getInterpolator() { return interpolator; }
}

RotatingTextSwitcher类

package libs.rotating_text;

import android.animation.ValueAnimator;
import android.app.Activity;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Path;
import android.text.DynamicLayout;
import android.text.Layout;
import android.text.SpannableStringBuilder;
import android.text.StaticLayout;
import android.text.TextPaint;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.util.TypedValue;

import androidx.appcompat.widget.AppCompatTextView;

import io.reactivex.Observable;
import io.reactivex.android.schedulers.AndroidSchedulers;
import io.reactivex.disposables.Disposable;
import io.reactivex.functions.Consumer;
import io.reactivex.schedulers.Schedulers;

import androidx.annotation.Nullable;

import java.util.Timer;
import java.util.TimerTask;
import java.util.concurrent.TimeUnit;

public class RotatingTextSwitcher extends AppCompatTextView {

    Disposable disposable;

    private TextPaint textPaint = new TextPaint();
    private String text = "", old_text = "";
    SpannableStringBuilder base = new SpannableStringBuilder(text);
    SpannableStringBuilder base_old = new SpannableStringBuilder(old_text);
    private DynamicLayout layout = new DynamicLayout(base, textPaint,500, Layout.Alignment.ALIGN_CENTER,1.0F,0.0F,true);
    private DynamicLayout layout_old = new DynamicLayout(base_old, textPaint,500, Layout.Alignment.ALIGN_CENTER,1.0F,0.0F,true);

    private Rotatable rotatable;
    private Paint paint;
    private Path path_in, path_out;

    public RotatingTextSwitcher(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);

        paint = getPaint();
        paint.setAntiAlias(true);
    }

    public void setRotatable(Rotatable rotatable) {
        this.rotatable = rotatable;
        initialize();
    }

    private void initialize() {
        text = rotatable.nextWord();
        base.clear();
        base.append(text);
        old_text = text;
        base_old.clear();
        base_old.append(old_text);
        setUpPath();
        setDisposable();
        scheduleUpdateTextTimer();
    }

    private void setDisposable() {
        disposable = Observable.interval(1000 / 60, TimeUnit.MILLISECONDS, Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(new Consumer<Long>() {
                    @Override
                    public void accept(Long aLong) {
                        invalidate();
                    }
                });
    }

    private void setUpPath() {
        post(new Runnable() {
            @Override
            public void run() {
                path_in = new Path();
                path_in.moveTo(0.0f, getHeight() - paint.getFontMetrics().bottom);
                path_in.lineTo(getWidth(), getHeight() - paint.getFontMetrics().bottom);
                rotatable.setPathIn(path_in);

                path_out = new Path();
                path_out.moveTo(0.0f, (2 * getHeight()) - paint.getFontMetrics().bottom);
                path_out.lineTo(getWidth(), (2 * getHeight()) - paint.getFontMetrics().bottom);
                rotatable.setPathOut(path_out);
            }
        });
    }

    private void scheduleUpdateTextTimer() {
        Timer update_text_timer = new Timer();
        update_text_timer.scheduleAtFixedRate(new TimerTask() {
            @Override
            public void run() {
                ((Activity) getContext()).runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        animateInHorizontal();
                        animateOutHorizontal();
                        old_text = text;
                        base_old.clear();
                        base_old.append(old_text);
                        text = rotatable.nextWord();
                        base.clear();
                        base.append(text);
                    }
                });
            }
        }, rotatable.getUpdateDuration(), rotatable.getUpdateDuration());
    }

    @Override
    protected void onDraw(Canvas canvas) {
        DisplayMetrics metrics = Resources.getSystem().getDisplayMetrics();
        float size = (int)TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, 32, metrics);
        textPaint.setTextSize(size);

        if (rotatable.getPathIn() != null) {
            layout.draw(canvas);
            //canvas.drawTextOnPath(text, rotatable.getPathIn(), 0.0f, 0.0f, paint);
        }
        if (rotatable.getPathOut() != null) {
            layout_old.draw(canvas);
            //canvas.drawTextOnPath(old_text, rotatable.getPathOut(), 0.0f, 0.0f, paint);
        }
        setHeight(layout.getHeight() + layout_old.getHeight());
    }

    private void animateInHorizontal() {
        ValueAnimator animator = ValueAnimator.ofFloat(0.0f, getHeight());
        animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator valueAnimator) {
                path_in = new Path();
                path_in.moveTo(0.0f, (Float) valueAnimator.getAnimatedValue() - paint.getFontMetrics().bottom);
                path_in.lineTo(getWidth(), (Float) valueAnimator.getAnimatedValue() - paint.getFontMetrics().bottom);
                rotatable.setPathIn(path_in);
            }
        });
        animator.setInterpolator(rotatable.getInterpolator());
        animator.setDuration(rotatable.getAnimationDuration());
        animator.start();
    }

    private void animateOutHorizontal() {
        ValueAnimator animator = ValueAnimator.ofFloat(getHeight(), getHeight() * 2.0f);
        animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator valueAnimator) {
                path_out = new Path();
                path_out.moveTo(0.0f, (Float) valueAnimator.getAnimatedValue() - paint.getFontMetrics().bottom);
                path_out.lineTo(getWidth(), (Float) valueAnimator.getAnimatedValue() - paint.getFontMetrics().bottom);
                rotatable.setPathOut(path_out);
            }
        });
        animator.setInterpolator(rotatable.getInterpolator());
        animator.setDuration(rotatable.getAnimationDuration());
        animator.start();
    }


}

一个布局

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <libs.rotating_text.RotatingTextSwitcher
        android:id="@+id/textView_presentation"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="50dp"
        android:textSize="35sp"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        />

</androidx.constraintlayout.widget.ConstraintLayout>

一个片段

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.AccelerateInterpolator;
import android.widget.ImageView;

import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;

import com.example.androidframework.R;

import libs.rotating_text.Rotatable;
import libs.rotating_text.RotatingTextSwitcher;

public class FragmentHomeSlide extends Fragment {

    private View inflated;
    private int drawable_id;
    private String[] text_presentation;

    @Override
    public void onCreate(@Nullable final Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        assert getArguments() != null;
        text_presentation = new String[];
        text_presentation[0] = "One row is set up with several words";
        text_presentation[1] = "This is another row";
    }

    @Override
    public View onCreateView(final LayoutInflater inflater, @Nullable final ViewGroup container, @Nullable final Bundle savedInstanceState) {
        inflated = inflater.inflate(R.layout.home_slide, container, false);
        setWidgets();
        return inflated;
    }

    private void setWidgets() {    
        final RotatingTextSwitcher rotating_presentation = inflated.findViewById(R.id.textView_presentation);
        rotating_presentation.setRotatable(new Rotatable(1000, 500, new AccelerateInterpolator(), text_presentation));
    }
}

1
你已经描述了问题,但没有说明你期望的解决方案。当行中有太多符号时,你希望看到什么? - azizbekian
1
不客气,先生。我刚刚阅读了您的问题,但是无法理解您的要求。我提出了问题,以便让其他读者也能明确。如果我有答案,我会考虑这个问题并给出答案。谢谢。 - azizbekian
@azizbekian,我在解决我的问题方面取得了很大的进展。现在我认为我知道出了什么问题:我没有使用DynamicLayout。所以现在我用它了...但是我无法使它沿着路径旋转。我已经编辑了问题。悬赏仍然有效 :-) 。 - JarsOfJam-Scheduler
1个回答

0

我的想法是根据你的问题限制更改输入...例如,如果你可以正确地写入20个字符,则将字符串数组更改为每行最多20个字符。

将此代码添加到可旋转构造函数中。

    ArrayList<String> newttext = new ArrayList<>();
    for (int i = 0; i < text.length; i++) {
        if (text[i].length() > 20){ // 20 is number characters
            ArrayList<String> strings = myCutter(text[i]);
            newttext.addAll(strings);
        }else{
            newttext.add(text[i]);
        }
    }

线条切割代码

    public ArrayList<String> myCutter(String s) {
    String trueLine = "";
    ArrayList<String> result = new ArrayList<>();
    if (s.length() > 20) {
        String[] split = s.split(" ");
        for (int i = 0; i < split.length; i++) {
            if (trueLine.length() + split[i].length() < 20) {
                trueLine = trueLine + " " + split[i];
            } else {
                result.add(trueLine);
                trueLine = "";
            }
        }
    } else {
        result.add(s);
    }
    return result;
}

当然这个答案不能被接受。不过还是谢谢你。 - JarsOfJam-Scheduler

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