需要直接查询系统库来获取手机上的全部文件信息，如：图片，视频，音频，pdf文件等等。

直接上代码，获取文件的方法：

@SuppressLint("Range")
public ArrayList<DataBean> getFiles(Context context) {ArrayList<DataBean> files = new ArrayList<>();Cursor c = null;try {String select = null;Uri contentUri = null;if (mUriType.equalsIgnoreCase("image")) {contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;} else if (mUriType.equalsIgnoreCase("video")) {contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;} else if (mUriType.equalsIgnoreCase("audio")) {select = "(_data NOT LIKE '%.amr')";contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;} else if (mUriType.equalsIgnoreCase("file")) {// 当前需求是：只支持pdf文件select = "(_data LIKE '%.pdf')";contentUri = MediaStore.Files.getContentUri("external");}ContentResolver mContentResolver = context.getContentResolver();c = mContentResolver.query(contentUri, null, select, null, null);if (c == null || c.getCount() == 0) {return new ArrayList<>();}int columnIndexOrThrowId = c.getColumnIndexOrThrow(MediaStore.Files.FileColumns._ID);int columnIndexOrThrowMimeType = c.getColumnIndexOrThrow(MediaStore.Files.FileColumns.MIME_TYPE);int columnIndexOrThrowData = c.getColumnIndexOrThrow(MediaStore.Files.FileColumns.DATA);int columnIndexOrThrowSize = c.getColumnIndexOrThrow(MediaStore.Files.FileColumns.SIZE);int columnIndexOrThrowTitle = c.getColumnIndexOrThrow(MediaStore.Files.FileColumns.TITLE);@SuppressLint("InlinedApi")int columnIndexOrThrowDuration = c.getColumnIndexOrThrow(MediaStore.Files.FileColumns.DURATION);int columnIndexOrThrowDataModified = c.getColumnIndexOrThrow(MediaStore.Files.FileColumns.DATE_MODIFIED);while (c.moveToNext()) {String path = c.getString(columnIndexOrThrowData);String minType = c.getString(columnIndexOrThrowMimeType);int position_do = path.lastIndexOf(".");if (position_do == -1) {continue;}int position_x = path.lastIndexOf(File.separator);if (position_x == -1) {continue;}String displayName = path.substring(position_x + 1);long size = c.getLong(columnIndexOrThrowSize);if (size == 0 || (mUriType.equalsIgnoreCase("video") &&size > 100*1024*1024L)) {continue;}String title = c.getString(columnIndexOrThrowTitle);long duration = c.getLong(columnIndexOrThrowDuration);long modifieDate = c.getLong(columnIndexOrThrowDataModified);long id = c.getInt(columnIndexOrThrowId);Uri uri = ContentUris.withAppendedId(contentUri, id);File file = new File(path);String time = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date(file.lastModified()));DataBean info = new DataBean();info.setName(displayName);info.setTime(title);info.setMinType(minType);info.setUri(uri);info.setPath(path);info.setSize(size);info.setDuration(duration);info.setUriType(mUriType);info.setId(id);info.setTime(time);info.setModifiedDate(modifieDate);files.add(info);}} catch (Exception e) {e.printStackTrace();} finally {if (c != null) {c.close();}}return files;
}

DataBean.jav类

public class DataBean implements Parcelable {private long id;private String name;private String title;private Uri uri;private String path;private String thumbPath;private long size;private long duration;private String time;private String minType;private long modifiedDate;private String uriType;private boolean checked = false;public DataBean() {}public DataBean(String minType, Uri uri, long fileSize, long duration) {this.minType = minType;this.uri = uri;this.size = fileSize;this.duration = duration;}public DataBean(Parcel in) {id = in.readLong();name = in.readString();title = in.readString();uri = in.readParcelable(Uri.class.getClassLoader());path = in.readString();thumbPath = in.readString();size = in.readLong();duration = in.readLong();time = in.readString();minType = in.readString();modifiedDate = in.readLong();uriType = in.readString();checked = in.readByte() != 0;}public static final Creator<DataBean> CREATOR = new Creator<DataBean>() {@Overridepublic DataBean createFromParcel(Parcel in) {return new DataBean(in);}@Overridepublic DataBean[] newArray(int size) {return new DataBean[size];}};public boolean isChecked() {return checked;}public void setChecked(boolean checked) {this.checked = checked;}public String getUriType() {return uriType;}public void setUriType(String uriType) {this.uriType = uriType;}public String getThumbPath() {return thumbPath;}public void setThumbPath(String thumbPath) {this.thumbPath = thumbPath;}public long getDuration() {return duration / 1000;}public void setDuration(long duration) {this.duration = duration;}public String getTitle() {return title;}public void setTitle(String title) {this.title = title;}public long getModifiedDate() {return modifiedDate;}public void setModifiedDate(long modifiedDate) {this.modifiedDate = modifiedDate;}public String getMinType() {return minType;}public void setMinType(String minType) {this.minType = minType;}public Uri getUri() {return uri;}public void setUri(Uri uri) {this.uri = uri;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getPath() {return path;}public void setPath(String path) {this.path = path;}public long getSize() {return size;}public void setSize(long size) {this.size = size;}public long getId() {return id;}public void setId(long id) {this.id = id;}public String getTime() {return time;}public void setTime(String time) {this.time = time;}@Overridepublic String toString() {return "DataBean{" +"id=" + id +", name='" + name + '\'' +", title='" + title + '\'' +", uri=" + uri +", path='" + path + '\'' +", thumbPath='" + thumbPath + '\'' +", size=" + size +", duration=" + duration +", time='" + time + '\'' +", minType='" + minType + '\'' +", modifiedDate=" + modifiedDate +", uriType='" + uriType + '\'' +", checked=" + checked +'}';}@Overridepublic int describeContents() {return 0;}@Overridepublic void writeToParcel(Parcel dest, int flags) {dest.writeLong(id);dest.writeString(name);dest.writeString(title);dest.writeParcelable(uri, flags);dest.writeString(path);dest.writeString(thumbPath);dest.writeLong(size);dest.writeLong(duration);dest.writeString(time);dest.writeString(minType);dest.writeLong(modifiedDate);dest.writeString(uriType);dest.writeByte((byte) (checked ? 1 : 0));}
}