一个简单的仿 Launcher 应用
本例实现两个功能：
- 系统桌面上的app图标能够排列在我们的页面上。
- 点击自定义桌面上的app图标,能够打开对应的app。
实现思路：
- 我们知道，一个应用的启动页 Activity 的 Intent 的 filter 中 包含
action为Intent.ACTION_MAIN和category为Intent.CATEGORY_LAUNCHER信息，我们构造一个这样的 Intent 来查询所有启动页 Activity 。 - 用一个 RecyclerView 来展示信息。
- 通过 Intent 跳转到对应 app 的主页面。
主要代码如下：
activity_main.xml
<?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"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.sharpcj.launchertest.MainActivity">
<android.support.v7.widget.RecyclerView
android:padding="10dp"
android:id="@+id/rv_test"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="Hello World!"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>
recyclerview_item.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="100dp"
android:layout_height="100dp">
<ImageView
android:id="@+id/iv_icon"
android:layout_width="70dp"
android:layout_height="70dp"
android:layout_marginLeft="15dp"
android:layout_marginTop="10dp"/>
<TextView
android:id="@+id/tv_name"
android:layout_width="wrap_content"
android:layout_height="15dp"
android:layout_marginTop="5dp"
android:textSize="13sp"
android:maxLines="1"
android:ellipsize="end"
android:layout_gravity="center_horizontal"
/>
</LinearLayout>
MainActivity.java
package com.example.sharpcj.launchertest;
import android.content.ComponentName;
import android.content.Intent;
import android.content.pm.ResolveInfo;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private RecyclerView mRvTest;
private List<ResolveInfo> mlsResolveInfo;
private RvTestAdapter mAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mRvTest = findViewById(R.id.rv_test);
mlsResolveInfo = new ArrayList<>();
mRvTest.setLayoutManager(new GridLayoutManager(this, 4));
mAdapter = new RvTestAdapter(MainActivity.this, mlsResolveInfo, new RvTestAdapter.OnItemClickListener() {
@Override
public void onClick(View view, int position) {
ResolveInfo resolveInfo = mlsResolveInfo.get(position);
startAppByResolveInfo(resolveInfo);
MainActivity.this.finish();
}
});
mRvTest.setAdapter(mAdapter);
List<ResolveInfo> resolveInfos = queryMainActivitiesInfo();
mlsResolveInfo.addAll(resolveInfos);
mAdapter.notifyDataSetChanged();
}
/**
* 查询所有包含启动 intent 的 Activity 信息（去掉本应用）
*
* @return
*/
private List<ResolveInfo> queryMainActivitiesInfo() {
Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);
mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);
List<ResolveInfo> resolveInfos = getPackageManager().queryIntentActivities(mainIntent, 0);
// 去掉本应用
Iterator<ResolveInfo> iterator = resolveInfos.iterator();
while (iterator.hasNext()) {
ResolveInfo resolveInfo = iterator.next();
String packageName = resolveInfo.activityInfo.packageName;
if (packageName.equals(getApplication().getPackageName())) {
iterator.remove();
}
}
return resolveInfos;
}
private void startAppByResolveInfo(ResolveInfo resolveInfo) {
String pkg = resolveInfo.activityInfo.packageName;
String cls = resolveInfo.activityInfo.name;
ComponentName componet = new ComponentName(pkg, cls);
//打开该应用的主activity
Intent intent = new Intent();
intent.setComponent(componet);
startActivity(intent);
}
}
RvTestAdapter.java
package com.example.sharpcj.launchertest;
import android.content.Context;
import android.content.pm.ResolveInfo;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import java.util.List;
/**
* Created by SharpCJ on 2018/7/26.
*/
public class RvTestAdapter extends RecyclerView.Adapter<RvTestAdapter.ViewHolder> {
public interface OnItemClickListener {
void onClick(View view, int position);
}
private Context mContext;
private List<ResolveInfo> mlsResolveInfo;
private OnItemClickListener mListener;
public RvTestAdapter(Context context, List<ResolveInfo> resolveInfos, OnItemClickListener listener) {
this.mContext = context;
this.mlsResolveInfo = resolveInfos;
this.mListener = listener;
}
public void setmListener(OnItemClickListener listener) {
this.mListener = listener;
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(mContext).inflate(R.layout.recyclerview_item, parent, false);
RvTestAdapter.ViewHolder viewHolder = new RvTestAdapter.ViewHolder(view, mListener);
return viewHolder;
}
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
ResolveInfo resolveInfo = mlsResolveInfo.get(position);
holder.imageView.setImageDrawable(resolveInfo.activityInfo.loadIcon(mContext.getPackageManager()));
holder.textView.setText(resolveInfo.activityInfo.applicationInfo.loadLabel(mContext.getPackageManager()));
}
@Override
public int getItemCount() {
return mlsResolveInfo.size();
}
class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
OnItemClickListener onItemClickListener;
ImageView imageView;
TextView textView;
public ViewHolder(View itemView, OnItemClickListener onItemClickListener) {
super(itemView);
this.onItemClickListener = onItemClickListener;
imageView = itemView.findViewById(R.id.iv_icon);
textView = itemView.findViewById(R.id.tv_name);
itemView.setOnClickListener(this);
}
@Override
public void onClick(View v) {
if (onItemClickListener != null) {
onItemClickListener.onClick(v, getAdapterPosition());
}
}
}
}
运行效果如图：
