Java-Android-工具栏未显示在活动中
作者：互联网
开发墙纸应用程序,并致力于迁移到API 21并删除ActionBar,而改用Toolbar.话虽如此,我正在尝试使用v7-support库.发生的基本上是工具栏应位于的灰色轮廓,但从未出现.
WallpaperActivity.java：
package com.death2all110.blisspapers;
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.Intent;
import android.graphics.drawable.Drawable;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Environment;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
import com.koushikdutta.urlimageviewhelper.UrlImageViewCallback;
import com.koushikdutta.urlimageviewhelper.UrlImageViewHelper;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
public class WallpaperActivity extends ActionBarActivity {
public final String TAG = "BlissPapers";
protected static final String MANIFEST = "wallpaper_manifest.xml";
protected static final int THUMBS_TO_SHOW = 4;
/*
* pull the manifest from the web server specified in config.xml or pull
* wallpaper_manifest.xml from local assets/ folder for testing
*/
public static final boolean USE_LOCAL_MANIFEST = false;
ArrayList<WallpaperCategory> categories = null;
ProgressDialog mLoadingDialog;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Window window = getWindow();
window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
window.clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
window.setStatusBarColor(getResources().getColor(R.color.primary_dark));
setContentView(R.layout.activity_wallpaper);
mLoadingDialog = new ProgressDialog(this);
mLoadingDialog.setCancelable(false);
mLoadingDialog.setIndeterminate(true);
mLoadingDialog.setMessage("Retreiving wallpapers from server...");
mLoadingDialog.show();
new LoadWallpaperManifest().execute();
Toolbar ab = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(ab);
getSupportActionBar().setTitle("Bliss Papers");
getSupportActionBar().setDisplayShowTitleEnabled(true);
UrlImageViewHelper.setErrorDrawable(getResources().getDrawable(com.death2all110.blisspapers.R.drawable.ic_error));
}
@Override
public void onResume() {
super.onResume();
Wallpaper.wallpapersCreated = 0;
}
protected void loadPreviewFragment() {
WallpaperPreviewFragment fragment = new WallpaperPreviewFragment();
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction ft = fragmentManager.beginTransaction();
ft.add(android.R.id.content, fragment);
ft.commit();
}
public static class WallpaperPreviewFragment extends Fragment {
static final String TAG = "PreviewFragment";
WallpaperActivity mActivity;
View mView;
public int currentPage = -1;
public int highestExistingIndex = 0;
Button back;
Button next;
TextView pageNum;
ThumbnailView[] thumbs;
protected int selectedCategory = 0; // *should* be <ALL> wallpapers
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
mActivity = (WallpaperActivity) getActivity();
next(); // load initial page
}
public void setCategory(int cat) {
selectedCategory = cat;
currentPage = -1;
next();
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
mView = inflater.inflate(com.death2all110.blisspapers.R.layout.activity_wallpaper, container, false);
back = (Button) mView.findViewById(com.death2all110.blisspapers.R.id.backButton);
next = (Button) mView.findViewById(com.death2all110.blisspapers.R.id.nextButton);
pageNum = (TextView) mView.findViewById(com.death2all110.blisspapers.R.id.textView1);
thumbs = new ThumbnailView[THUMBS_TO_SHOW];
thumbs[0] = (ThumbnailView) mView.findViewById(com.death2all110.blisspapers.R.id.imageView1);
thumbs[1] = (ThumbnailView) mView.findViewById(com.death2all110.blisspapers.R.id.imageView2);
thumbs[2] = (ThumbnailView) mView.findViewById(com.death2all110.blisspapers.R.id.imageView3);
thumbs[3] = (ThumbnailView) mView.findViewById(com.death2all110.blisspapers.R.id.imageView4);
next.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
next();
}
});
back.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
previous();
}
});
return mView;
}
public ArrayList<WallpaperCategory> getCategories() {
return mActivity.categories;
}
protected Wallpaper getWallpaper(int realIndex) {
return getCategories().get(selectedCategory).getWallpapers().get(realIndex);
}
protected void setThumbs() {
for (ThumbnailView v : thumbs)
v.setVisibility(View.INVISIBLE);
final int numWallpapersInCategory = getCategories().get(selectedCategory)
.getWallpapers().size();
boolean enableForward = true;
for (int i = 0; i < thumbs.length; i++) {
final int realIndex = (currentPage * thumbs.length + i);
if (realIndex >= (numWallpapersInCategory - 1)) {
enableForward = false;
break;
}
Wallpaper w = getWallpaper(realIndex);
thumbs[i].setOnClickListener(null);
thumbs[i].getName().setText(w.getName());
thumbs[i].getAuthor().setText(w.getAuthor());
UrlImageViewHelper.setUrlDrawable(thumbs[i].getThumbnail(), w.getThumbUrl(),
com.death2all110.blisspapers.R.drawable.ic_placeholder, new ThumbnailCallBack(w, realIndex));
}
back.setEnabled(currentPage != 0);
next.setEnabled(enableForward);
}
public void next() {
getNextButton().setEnabled(false);
pageNum.setText(getResources().getString(com.death2all110.blisspapers.R.string.page) + " " + (++currentPage + 1));
setThumbs();
}
public void previous() {
pageNum.setText(getResources().getString(com.death2all110.blisspapers.R.string.page) + " " + (--currentPage + 1));
setThumbs();
}
protected void skipToPage(int page) {
if (page < currentPage) {
while (page < currentPage) {
previous(); // should subtract page
}
} else if (page > currentPage) {
while (page > currentPage) {
next();
}
}
}
public void jumpTo() {
// View view = getLayoutInflater().inflate(R.layout.dialog_jumpto,
// null);
// final EditText e = (EditText) view.findViewById(R.id.pageNumber);
// AlertDialog.Builder j = new AlertDialog.Builder(this);
// j.setTitle(R.string.jump2);
// j.setView(view);
// j.setPositiveButton(android.R.string.ok, new
// DialogInterface.OnClickListener() {
//
// public void onClick(DialogInterface dialog, int which) {
// skipToPage(Integer.parseInt(e.getText().toString()));
// }
// });
// j.setNegativeButton(android.R.string.no, new
// DialogInterface.OnClickListener() {
//
// public void onClick(DialogInterface dialog, int which) {
// dialog.cancel();
// }
// });
// j.create().show();
}
protected View getThumbView(int i) {
if (thumbs != null && thumbs.length > 0)
return thumbs[i];
else
return null;
}
protected Button getNextButton() {
return next;
}
protected Button getPreviousButton() {
return back;
}
@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
super.onCreateOptionsMenu(menu, inflater);
}
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case com.death2all110.blisspapers.R.id.jump:
jumpTo();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
class ThumbnailCallBack implements UrlImageViewCallback {
Wallpaper wall;
int index;
public ThumbnailCallBack(Wallpaper wall, int index) {
this.wall = wall;
this.index = index;
}
@Override
public void onl oaded(ImageView imageView, Drawable loadedDrawable, String url,
boolean loadedFromCache, boolean error) {
final int relativeIndex = index % 4;
if (!error) {
getThumbView(relativeIndex).setOnClickListener(
new ThumbnailClickListener(wall));
}
getThumbView(relativeIndex).setVisibility(View.VISIBLE);
if (relativeIndex == 3)
getNextButton().setEnabled(true);
}
}
class ThumbnailClickListener implements View.OnClickListener {
Wallpaper wall;
public ThumbnailClickListener(Wallpaper wallpaper) {
this.wall = wallpaper;
}
@Override
public void onClick(View v) {
Intent preview = new Intent(mActivity, Preview.class);
preview.putExtra("wp", wall.getUrl());
startActivity(preview);
}
}
}
public static String getDlDir(Context c) {
String configFolder = getResourceString(c, com.death2all110.blisspapers.R.string.config_wallpaper_download_loc);
if (configFolder != null && !configFolder.isEmpty()) {
return new File(Environment.getExternalStorageDirectory(), configFolder)
.getAbsolutePath() + "/";
} else {
return Environment.getExternalStorageDirectory().getAbsolutePath();
}
}
public static String getSvDir(Context c) {
String configFolder = getResourceString(c, com.death2all110.blisspapers.R.string.config_wallpaper_sdcard_dl_location);
if (configFolder != null && !configFolder.isEmpty()) {
return new File(Environment.getExternalStorageDirectory(), configFolder)
.getAbsolutePath() + "/";
} else {
return null;
}
}
protected String getWallpaperDestinationPath() {
String configFolder = getResourceString(com.death2all110.blisspapers.R.string.config_wallpaper_sdcard_dl_location);
if (configFolder != null && !configFolder.isEmpty()) {
return new File(Environment.getExternalStorageDirectory(), configFolder)
.getAbsolutePath();
}
// couldn't find resource?
return null;
}
protected String getResourceString(int stringId) {
return getApplicationContext().getResources().getString(stringId);
}
public static String getResourceString(Context c, int id) {
return c.getResources().getString(id);
}
private class LoadWallpaperManifest extends
AsyncTask<Void, Boolean, ArrayList<WallpaperCategory>> {
@Override
protected ArrayList<WallpaperCategory> doInBackground(Void... v) {
try {
InputStream input = null;
if (USE_LOCAL_MANIFEST) {
input = getApplicationContext().getAssets().open(MANIFEST);
} else {
URL url = new URL(getResourceString(com.death2all110.blisspapers.R.string.config_wallpaper_manifest_url));
URLConnection connection = url.openConnection();
connection.connect();
// this will be useful so that you can show a typical
// 0-100%
// progress bar
int fileLength = connection.getContentLength();
// download the file
input = new BufferedInputStream(url.openStream());
}
OutputStream output = getApplicationContext().openFileOutput(
MANIFEST, MODE_PRIVATE);
byte data[] = new byte[1024];
long total = 0;
int count;
while ((count = input.read(data)) != -1) {
total += count;
// publishing the progress....
// publishProgress((int) (total * 100 / fileLength));
output.write(data, 0, count);
}
output.flush();
output.close();
input.close();
// file finished downloading, parse it!
ManifestXmlParser parser = new ManifestXmlParser();
return parser.parse(new File(getApplicationContext().getFilesDir(), MANIFEST),
getApplicationContext());
} catch (Exception e) {
Log.d(TAG, "Exception!", e);
}
return null;
}
@Override
protected void onPostExecute(ArrayList<WallpaperCategory> result) {
categories = result;
if (categories != null)
loadPreviewFragment();
mLoadingDialog.cancel();
super.onPostExecute(result);
}
}
}
这是activity_wallpaper.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<View
android:id="@+id/strut"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_centerHorizontal="true" />
<Button
android:id="@+id/backButton"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:layout_alignRight="@id/strut"
android:layout_marginBottom="5dp"
android:text="@string/back" />
<Button
android:id="@+id/nextButton"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_alignLeft="@id/strut"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_marginBottom="5dp"
android:text="@string/next" />
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/backButton"
android:layout_centerHorizontal="true"
android:layout_marginBottom="5dp"
android:text="@string/page" />
<LinearLayout
android:id="@+id/LinearLayout1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_above="@id/textView1"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
android:layout_marginBottom="5dp"
android:orientation="vertical" >
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:minHeight="?android:attr/actionBarSize"
android:background="?android:attr/colorPrimary" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:orientation="horizontal" >
<com.death2all110.blisspapers.ThumbnailView
android:id="@+id/imageView1"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_marginBottom="5dp"
android:layout_marginLeft="5dp"
android:layout_marginRight="5dp"
android:layout_marginTop="5dp"
android:layout_weight="1" />
<com.death2all110.blisspapers.ThumbnailView
android:id="@+id/imageView2"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_marginBottom="5dp"
android:layout_marginLeft="5dp"
android:layout_marginRight="5dp"
android:layout_marginTop="5dp"
android:layout_weight="1" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:orientation="horizontal" >
<com.death2all110.blisspapers.ThumbnailView
android:id="@+id/imageView3"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_marginBottom="5dp"
android:layout_marginLeft="5dp"
android:layout_marginRight="5dp"
android:layout_marginTop="5dp"
android:layout_weight="1" />
<com.death2all110.blisspapers.ThumbnailView
android:id="@+id/imageView4"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_marginBottom="5dp"
android:layout_marginLeft="5dp"
android:layout_marginRight="5dp"
android:layout_marginTop="5dp"
android:layout_weight="1" />
</LinearLayout>
</LinearLayout>
</RelativeLayout>
styles.xml：
<resources>
<style name="Theme.Bliss" parent="Theme.AppCompat.NoActionBar">
<!-- Main theme colors -->
<!-- your app branding color for the app bar -->
<item name="colorPrimary">@color/primary</item>
<!-- darker variant for the status bar and contextual app bars -->
<item name="colorPrimaryDark">@color/primary_dark</item>
<!-- theme UI controls like checkboxes and text fields -->
<item name="colorAccent">@color/accent</item>
</style>
</resources>
如果我从onCreate方法中删除setContentView,则会收到错误消息：
java.lang.NullPointerException：尝试在空对象引用上调用虚拟方法’java.lang.CharSequence android.support.v7.widget.Toolbar.getTitle()’
我有什么办法可以纠正这个问题？
屏幕截图：
解决方法:
您需要在布局中添加android.supprt.v7.widget.Toolbar,然后在ActionBarActivity的onCreate方法中执行此操作
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActitionBar(toolbar);
此外,请确保您的主题使用Theme.AppCompat.NoActionBar(或Theme.AppCompat.Light.NoActionBar)
标签：material-design,android-support-library,java,android 来源： https://codeday.me/bug/20191028/1955821.html