java - 为什么 RecyclerView 在 ToolBar 上膨胀?
问题描述
当我为 recyclerview 充气时,我的应用程序出现问题。在recyclerview内部,一些卡片被充气,当它出现在屏幕上时,工具栏消失并且无法使用设置按钮。
使用最新的 SDK 和库版本。
活动主.xml:
<?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"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/linearLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<androidx.appcompat.widget.Toolbar
android:id="@+id/toolbar"
android:minHeight="?attr/actionBarSize"
android:layout_width="match_parent"
android:layout_height="wrap_content"
tools:ignore="MissingConstraints">
</androidx.appcompat.widget.Toolbar>
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/conteudoRSS"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/toolbar" />
</androidx.constraintlayout.widget.ConstraintLayout>
linha.xml -> 在这里我得到了用于在 recyclerview 上显示项目的卡片视图
<?xml version="1.0" encoding="utf-8"?>
<androidx.cardview.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
style="@style/CardView.Light"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="5dp">
<androidx.constraintlayout.widget.ConstraintLayout xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="5dp">
<TextView
android:id="@+id/titulo"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_margin="16dp"
android:textAppearance="@style/TextAppearance.AppCompat.Title"
android:textColor="#000000"
tools:text="Titulo Noticia"
app:layout_constraintEnd_toStartOf="@+id/imagem"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="@+id/dataPublicacao"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:textAppearance="@style/TextAppearance.AppCompat.Body1"
android:textColor="#8A000000"
tools:text="18 Setembro 2020"
app:layout_constraintEnd_toStartOf="@+id/imagem"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/titulo" />
<ImageView
android:id="@+id/imagem"
android:layout_width="140dp"
android:layout_height="140dp"
android:layout_margin="12dp"
tools:background="@color/colorAccent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="@+id/url"
android:layout_width="0dp"
android:layout_height="0dp"
android:visibility="invisible"
tools:ignore="MissingConstraints"
app:layout_constraintTop_toBottomOf="@+id/dataPublicacao" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.cardview.widget.CardView>
MainActivity.java
package br.ufpe.cin.android.rss;
import androidx.appcompat.app.AppCompatActivity;
package br.ufpe.cin.android.rss;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import androidx.preference.PreferenceManager;
import androidx.recyclerview.widget.DividerItemDecoration;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import com.prof.rssparser.Article;
import com.prof.rssparser.Channel;
import com.prof.rssparser.OnTaskCompleted;
import com.prof.rssparser.Parser;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.nio.charset.StandardCharsets;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private String urlFeed;
private Toolbar mTopToolbar;
RecyclerView conteudoRSS;
List<Article> noticias;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
conteudoRSS = findViewById(R.id.conteudoRSS);
mTopToolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(mTopToolbar);
SharedPreferences preferences = getSharedPreferences
("user_preferences", MODE_PRIVATE);
SharedPreferences.Editor editor = preferences.edit();
editor.putString("feed1", getString(R.string.feed1));
editor.putString("feed2", getString(R.string.feed2));
editor.putString("feed3", getString(R.string.feed3));
editor.apply();
if(preferences.contains("rssfeed")){
urlFeed = preferences.getString("rssfeed", getString(R.string.feed_padrao));
} else {
editor.putString("rssfeed", getString(R.string.feed_padrao));
editor.apply();
urlFeed = preferences.getString("rssfeed", getString(R.string.feed_padrao));
}
conteudoRSS = new RecyclerView(this);
conteudoRSS.setLayoutManager(new LinearLayoutManager(this));
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
if (item.getItemId() == R.id.action_settings) {
startActivity(new Intent(
this, PreferenciasActivity.class));
return true;
} else {
return super.onOptionsItemSelected(item);
}
}
@Override
protected void onStart() {
super.onStart();
Parser p = new Parser.Builder().build();
p.onFinish(
new OnTaskCompleted() {
@Override
public void onTaskCompleted(Channel channel) {
noticias = channel.getArticles();
runOnUiThread(
() -> {
RssAdapter adapter = new RssAdapter(
getApplicationContext(),
noticias
);
conteudoRSS.setAdapter(adapter);
setContentView(conteudoRSS);
}
);
}
@Override
public void onError(Exception e) {
Log.e("RSS_APP",e.getMessage());
}
}
);
p.execute(urlFeed);
}
protected void onResume() {
super.onResume();
}
private String getRssFeed(String feed) throws IOException {
InputStream in = null;
String rssFeed;
try {
URL url = new URL(feed);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
in = conn.getInputStream();
ByteArrayOutputStream out = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
for (int count; (count = in.read(buffer)) != -1; ) {
out.write(buffer, 0, count);
}
byte[] response = out.toByteArray();
rssFeed = new String(response, StandardCharsets.UTF_8);
} finally {
if (in != null) {
in.close();
}
}
return rssFeed;
}
}
conteudoRSS = new RecyclerView(this);
conteudoRSS.setLayoutManager(new LinearLayoutManager(this));
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
if (item.getItemId() == R.id.action_settings) {
startActivity(new Intent(
this, PreferenciasActivity.class));
return true;
} else {
return super.onOptionsItemSelected(item);
}
}
@Override
protected void onStart() {
super.onStart();
Parser p = new Parser.Builder().build();
p.onFinish(
new OnTaskCompleted() {
@Override
public void onTaskCompleted(Channel channel) {
noticias = channel.getArticles();
runOnUiThread(
() -> {
RssAdapter adapter = new RssAdapter(
getApplicationContext(),
noticias
);
conteudoRSS.setAdapter(adapter);
setContentView(conteudoRSS);
}
);
}
@Override
public void onError(Exception e) {
Log.e("RSS_APP",e.getMessage());
}
}
);
p.execute(urlFeed);
}
protected void onResume() {
super.onResume();
}
private String getRssFeed(String feed) throws IOException {
InputStream in = null;
String rssFeed;
try {
URL url = new URL(feed);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
in = conn.getInputStream();
ByteArrayOutputStream out = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
for (int count; (count = in.read(buffer)) != -1; ) {
out.write(buffer, 0, count);
}
byte[] response = out.toByteArray();
rssFeed = new String(response, StandardCharsets.UTF_8);
} finally {
if (in != null) {
in.close();
}
}
return rssFeed;
}
}
ItemRssViewHolder.java
package br.ufpe.cin.android.rss;
import android.content.Intent;
import android.net.Uri;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
import androidx.recyclerview.widget.RecyclerView;
public class ItemRssViewHolder extends RecyclerView.ViewHolder {
TextView titulo = null;
ImageView image = null;
TextView data = null;
TextView url = null;
public ItemRssViewHolder(View itemCard) {
super(itemCard);
this.titulo = itemCard.findViewById(R.id.titulo);
this.image = itemCard.findViewById(R.id.imagem);
this.data = itemCard.findViewById(R.id.dataPublicacao);
this.url = itemCard.findViewById(R.id.url);
itemCard.setOnClickListener(
v -> {
String uri = url.getText().toString();
Intent intent = new Intent(Intent.ACTION_VIEW,
Uri.parse(uri));
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
itemCard.getContext().startActivity(intent);
}
);
}
}
RssAdapter.java
package br.ufpe.cin.android.rss;
import android.content.Context;
import android.net.Uri;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;
import com.prof.rssparser.Article;
import com.squareup.picasso.Picasso;
import java.util.List;
import static br.ufpe.cin.android.rss.R.layout.linha;
public class RssAdapter extends RecyclerView.Adapter <ItemRssViewHolder> {
List<Article> noticias;
Context context;
public RssAdapter(Context c, List<Article> noticias) {
this.noticias = noticias;
this.context = c;
}
public int getCount() {
return noticias.size();
}
public Object getItem(int i) {
return noticias.get(i);
}
@NonNull
@Override
public ItemRssViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
LayoutInflater inflater = LayoutInflater.from(context);
View v = inflater.inflate(R.layout.linha, parent, false);
ItemRssViewHolder viewHolder = new ItemRssViewHolder(v);
return viewHolder;
}
@Override
public void onBindViewHolder(@NonNull ItemRssViewHolder viewHolder, int i) {
Article noticia = noticias.get(i);
viewHolder.titulo.setText(noticia.getTitle());
viewHolder.data.setText("Publicado em: " + noticia.getPubDate().substring(0, 22));
viewHolder.url.setText(noticia.getLink());
String url = noticias.get(i).getImage();
Picasso.with(context)
.load(url)
.into(viewHolder.image);
}
@Override
public long getItemId(int i) {
return i;
}
@Override
public int getItemCount() {
return noticias.size();
}
}
解决方案
因为您将 Recyclerview 的顶部与父级 (ConstraintLayout) 的顶部对齐,所以它在工具栏上方。
替换app:layout_constraintTop_toTopOf="parent"
为app:layout_constraintTop_toBottomOf="@id/toolbar"
以将 Recyclerview 的顶部与 Toolbar 的底部对齐
将这些属性添加到您的工具栏:
app:layout_constraintBottom_toTopOf="@id/conteudoRSS"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
<?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"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/linearLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<androidx.appcompat.widget.Toolbar
android:id="@+id/toolbar"
android:minHeight="?attr/actionBarSize"
android:layout_width="0dp"
android:layout_height="wrap_content"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toTopOf="@id/conteudoRSS"
tools:ignore="MissingConstraints">
</androidx.appcompat.widget.Toolbar>
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/conteudoRSS"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@id/toolbar"/> <!-- replace app:layout_constraintTop_toTopOf="parent" -->
</androidx.constraintlayout.widget.ConstraintLayout>
LinearLayout 也不错,在这种情况下比 ConstraintLayout 更简单
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/linearLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity">
<androidx.appcompat.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize">
</androidx.appcompat.widget.Toolbar>
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/conteudoRSS"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"/>
</LinearLayout>
推荐阅读
- reactjs - React:创建简单的管理面板并获取 TypeError: headers is undefined
- c# - 如何在 ASP.NET Core Razor 页面中编写自定义标签?
- python - 如果没有图像处理 python 库(Pillow 和 cv2)无法读取,如何解码这个二进制图像文件?
- c++ - 在没有编译器的机器上安装并运行 c++ 程序
- android - 错误:index.js:找不到模块'babel-plugin-r' React Native
- php - 如何从 word-press 标题中删除单词存档
- javascript - 如何在 Drawer.Screens 之间放置内容
- postgresql - 将数组中的值相加时出现类型转换问题(array_agg)
- python - 如何在python中将变量从一个类获取到另一个类
- spring-boot - 为什么使用 netty-http 会立即关闭骆驼上下文,而使用骆驼码头则不会?