约束布局未正确显示

Question

我正在开发新闻Android应用程序我跟随流行新闻应用程序ui但它显示非常模糊的下面的图片current screenshot of app

followscreenshot I want to achieve截图，我想实现

在我的article_list.xml下面

<ImageView
    android:id="@+id/articleImage"
    android:layout_width="408dp"
    android:layout_height="208dp"
    android:layout_gravity="center"
    app:layout_constraintRight_toRightOf="parent"
    tools:ignore="MissingConstraints" />

<TextView
    android:id="@+id/articleAuthor"
    android:layout_width="136dp"
    android:layout_height="75dp"
    android:gravity="start"
    android:text="@string/article_author"
    android:textSize="12sp"
    app:layout_constraintLeft_toLeftOf="parent"
    tools:ignore="MissingConstraints"
    tools:layout_editor_absoluteY="219dp" />

<TextView
    android:id="@+id/articleTitle"
    android:layout_width="160dp"
    android:layout_height="78dp"
    android:text="@string/article_title"
    android:textColor="@color/colorBlack"
    android:textSize="28sp"
    tools:ignore="MissingConstraints"
    tools:layout_editor_absoluteX="3dp"
    tools:layout_editor_absoluteY="325dp" />


<TextView
    android:id="@+id/articleTime"
    android:layout_width="160dp"
    android:layout_height="78dp"
    android:text="Article Time"
    android:textSize="28sp"
    tools:ignore="MissingConstraints"
    tools:layout_editor_absoluteX="3dp"
    tools:layout_editor_absoluteY="459dp" />

<ImageButton
    android:id="@+id/articleShare"
    android:layout_width="139dp"
    android:layout_height="60dp"
    android:src="@drawable/ic_share"
    android:background="@color/colorWhite"
    tools:ignore="MissingConstraints"
    tools:layout_editor_absoluteX="115dp"
    tools:layout_editor_absoluteY="558dp" />


<ImageButton
    android:id="@+id/articleFavorite"
    android:layout_width="139dp"
    android:layout_height="60dp"
    android:background="@color/colorWhite"
    android:src="@drawable/ic_bookmark"
    tools:ignore="MissingConstraints"
    tools:layout_editor_absoluteX="272dp"
    tools:layout_editor_absoluteY="558dp" />

在我的适配器类下面

公共类ArticleAdapter扩展了RecyclerView.Adapter {

public static final String urlKey = "urlKey";
public static final String imageKey = "imageKey";
public ArticleAdapter.ClickListener listener;
private ClipboardManager myClipboard;
private ClipData myClip;
Context context;
private List<Article> articles = new ArrayList<>();


public ArticleAdapter(List<Article> articles, SportNews sportNews) {
    this.articles = articles;
    this.listener = listener;

}

public ArticleAdapter(ArticleAdapter.ClickListener clickListener) {
}

@NonNull
@Override
public CustomViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
    View itemView = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.article_list, null);
    return new CustomViewHolder(itemView);
}

@Override
public void onBindViewHolder(@NonNull CustomViewHolder customViewHolder, int position) {
    Article article = articles.get(position);
    SimpleDateFormat input = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
    SimpleDateFormat output = new SimpleDateFormat("dd/MM/yyyy");

    Date d = new Date();
    try {
        d = input.parse(article.getPublishedAt());
    } catch (ParseException e) {
        e.printStackTrace();
    }


    String formatted = output.format(d);
    if (article != null) {
        customViewHolder.articleAuthor.setText(article.getAuthor());
        customViewHolder.articleTitle.setText(article.getTitle());
        customViewHolder.articleTime.setText(formatted);
        Picasso.get().load(article.getUrlToImage()).into(customViewHolder.articleImage);
    }
    customViewHolder.itemView.setOnClickListener(v -> {
        Intent intent = new Intent(v.getContext(), DetailActivity.class);

        intent.putExtra("urlKey", article.getUrl());

        v.getContext().startActivity(intent);
    });
    customViewHolder.articleShare.setOnClickListener(v -> {
        Intent sharingIntent = new Intent(android.content.Intent.ACTION_SEND);
        sharingIntent.setType("text/plain");
        String articleDescription = article.getDescription();
        String articleTitle = article.getTitle();
        sharingIntent.putExtra(android.content.Intent.EXTRA_SUBJECT, articleDescription);
        sharingIntent.putExtra(android.content.Intent.EXTRA_TEXT, articleTitle);
        v.getContext().startActivity((Intent.createChooser(sharingIntent, "Share using")));


    });

    customViewHolder.articleFavorite.setOnClickListener(v -> {
        myClipboard = (ClipboardManager) v.getContext().getSystemService(Context.CLIPBOARD_SERVICE);


        myClip = ClipData.newPlainText("label", customViewHolder.articleTitle.getText().toString());
        myClipboard.setPrimaryClip(myClip);
        Toast.makeText(v.getContext(), "Copied to clipboard", Toast.LENGTH_SHORT).show();

    });

}


@Override
public int getItemCount() {
    if (articles == null) return 0;
    return articles.size();
}

public interface ClickListener {
}

public class CustomViewHolder extends RecyclerView.ViewHolder {
    @BindView(R.id.articleAuthor)
    TextView articleAuthor;
    @BindView(R.id.articleTitle)
    TextView articleTitle;
    @BindView(R.id.articleTime)
    TextView articleTime;
    @BindView(R.id.articleShare)
    ImageButton articleShare;
    @BindView(R.id.articleFavorite)
    ImageButton articleFavorite;
    @BindView(R.id.articleImage)
    ImageView articleImage;


    public CustomViewHolder(View view) {
        super(view);
        ButterKnife.bind(this, view);
      }
  }
}

Answer 1

您的问题是您没有在视图上设置正确的约束。

tools属性仅影响预览而不影响实际实现。所以每次你有像这样的tools:layout_editor_absoluteX="3dp"，你只是在预览中移动视图而不是实际的实现。
您需要在视图上设置正确的约束。例如，如果您的图像需要位于父视图app:layout_constraintRight_toRightOf="parent"和app:layout_constraintTop_toTopOf="parent"的右上角
你需要相互约束视图，例如，如果articleTitle需要位于父级的左侧并且位于articleAuthor下面，那么在articleTitle中你需要设置：app:layout_constraintLeft_toLeftOf="parent"和app:layout_constraintTop_toBottomOf="@id/articleAuthor"

我强烈建议您删除所有tools:ignore="MissingConstraints"，IDE将实际告诉您每个视图缺少什么约束。

最后，您应该看一下本页底部的示例：https://developer.android.com/training/constraint-layout

Answer 2

您错过了很多约束，此外，您还在视图上使用了固定大小。由于不同的手机使用固定大小的屏幕尺寸不同会使您的屏幕无法响应所有屏幕尺寸。

如果你想避免这种情况，你可以使用Guildelines来确定你的视图宽度和高度，这样你的布局就适合所有的屏幕尺寸。

以下是使用ConstraintLayout的示例：

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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">

<ImageView
    android:id="@+id/articleImage"
    android:layout_width="0dp"
    android:layout_height="0dp"
    android:layout_gravity="center"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginBottom="8dp"
    app:layout_constraintBottom_toTopOf="@+id/guideline6"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="@+id/guideline4"
    app:layout_constraintTop_toTopOf="parent" />

<TextView
    android:id="@+id/articleAuthor"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    android:layout_marginEnd="8dp"
    android:gravity="start"
    android:text="article_author"
    android:textSize="12sp"
    app:layout_constraintEnd_toStartOf="@+id/guideline4"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent" />

<TextView
    android:id="@+id/articleTitle"
    android:layout_width="0dp"
    android:layout_height="0dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginBottom="8dp"
    android:text="article_title"
    android:textSize="28sp"
    app:layout_constraintBottom_toBottomOf="@+id/articleImage"
    app:layout_constraintEnd_toStartOf="@+id/guideline4"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/articleAuthor" />


<TextView
    android:id="@+id/articleTime"
    android:layout_width="0dp"
    android:layout_height="0dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    android:layout_marginBottom="8dp"
    android:text="Article Time"
    android:textSize="18sp"
    app:layout_constraintBottom_toTopOf="@+id/guideline5"
    app:layout_constraintEnd_toStartOf="@+id/articleFavorite"
    app:layout_constraintHorizontal_bias="0.5"
    app:layout_constraintStart_toStartOf="@+id/articleTitle"
    app:layout_constraintTop_toTopOf="@+id/guideline6" />

<ImageButton
    android:id="@+id/articleShare"
    android:layout_width="0dp"
    android:layout_height="0dp"
    android:layout_marginEnd="8dp"
    app:layout_constraintBottom_toBottomOf="@+id/articleTime"
    app:layout_constraintEnd_toStartOf="@+id/guideline4"
    app:layout_constraintHorizontal_bias="0.5"
    app:layout_constraintStart_toEndOf="@+id/articleFavorite"
    app:layout_constraintTop_toTopOf="@+id/articleTime" />


<ImageButton
    android:id="@+id/articleFavorite"
    android:layout_width="0dp"
    android:layout_height="0dp"
    app:layout_constraintBottom_toBottomOf="@+id/articleTime"
    app:layout_constraintEnd_toStartOf="@+id/articleShare"
    app:layout_constraintHorizontal_bias="0.5"
    app:layout_constraintStart_toEndOf="@+id/articleTime"
    app:layout_constraintTop_toTopOf="@+id/articleTime" />

<android.support.constraint.Guideline
    android:id="@+id/guideline4"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    app:layout_constraintGuide_percent="0.5" />

<android.support.constraint.Guideline
    android:id="@+id/guideline6"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="horizontal"
    app:layout_constraintGuide_percent="0.3" />

<android.support.constraint.Guideline
    android:id="@+id/guideline5"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="horizontal"
    app:layout_constraintGuide_percent="0.4"/>
</android.support.constraint.ConstraintLayout>

它看起来像这样：

如果您想更改视图尺寸，只需移动指南，所有布局都将相应适合。

我可以给你一些提示 - 不要使用tools:ignore="MissingConstraints"，因为这个属性只会影响预览，你在预览和运行时看到的内容将不一样。

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