Android实现极简打开摄像头
很多时候忘记android摄像头如何打开，查看google文档的话，发现太复杂（只是单纯的想打开摄像头而已，不想添加那么多设置，添加那么功能），很多博客也是对官方文档的小修小改，连方法名都一样，因此，我决定完成android相机最简单的打开摄像头（仅仅打开）。很久没用忘掉的话，打开链接复制粘贴一下就完事了。
androidmanifest.xml设置camera权限后，在代码中还要设置权限检查，但是因为我连权限检查都懒得加了，装好后直接在手机系统里手动允许权限。
camera1（已废弃）：
xml中使用surfaceview作为预览view
<?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:layout_width="match_parent" android:layout_height="match_parent" tools:context=".mainactivity"> <surfaceview android:id="@+id/surfaceview" android:layout_width="0dp" android:layout_height="0dp" app:layout_constraintbottom_tobottomof="parent" app:layout_constraintleft_toleftof="parent" app:layout_constraintright_torightof="parent" app:layout_constrainttop_totopof="parent" /> </androidx.constraintlayout.widget.constraintlayout>
mainactivity:
public class mainactivity extends appcompatactivity implements surfaceholder.callback{
private surfaceholder holder;
private camera camera;
@override
protected void oncreate(bundle savedinstancestate) {
super.oncreate(savedinstancestate);
requestwindowfeature(window.feature_no_title);
getwindow().setflags(windowmanager.layoutparams.flag_fullscreen,
windowmanager.layoutparams.flag_fullscreen);
setcontentview(r.layout.activity_main);
surfaceview surfaceview = findviewbyid(r.id.surfaceview);
holder = surfaceview.getholder();
holder.addcallback(this);
}
@override
public void surfacecreated(surfaceholder holder) {
if(camera == null){
try {
camera = camera.open(camera.camerainfo.camera_facing_back);
camera.setpreviewdisplay(holder);
camera.startpreview();
camera.parameters parameters = camera.getparameters();
parameters.setfocusmode(camera.parameters.focus_mode_auto);
parameters.setflashmode(camera.parameters.flash_mode_auto);
camera.setparameters(parameters);
camera.setdisplayorientation(90);
}catch (exception e){
e.printstacktrace();
}
}
}
}这样就完成了最简单的打开摄像头并在手机中出现画面。（代码里去掉2个接口中未实现的方法）
camera2
android 5.0（api 21）以后，谷歌就决定废弃原有的camera api改用camera2 api，因为功能更强大
xml使用textureview作为预览（其实surfaceview也行，官方的demo是用textureview的一个子类）：
<?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:layout_width="match_parent" android:layout_height="match_parent" tools:context=".mainactivity"> <textureview android:id="@+id/surfaceview" android:layout_width="0dp" android:layout_height="0dp" app:layout_constraintbottom_tobottomof="parent" app:layout_constraintleft_toleftof="parent" app:layout_constraintright_torightof="parent" app:layout_constrainttop_totopof="parent" /> </androidx.constraintlayout.widget.constraintlayout>
mainactivity:
public class mainactivity extends appcompatactivity implements textureview.surfacetexturelistener {
private textureview textureview;
private capturerequest.builder builder;
@override
protected void oncreate(bundle savedinstancestate) {
super.oncreate(savedinstancestate);
setcontentview(r.layout.activity_main);
textureview = findviewbyid(r.id.surfaceview);
textureview.setsurfacetexturelistener(this);
}
@override
public void onsurfacetextureavailable(final surfacetexture surface, int width, int height) {
cameramanager manager = (cameramanager) getsystemservice(camera_service);
if (activitycompat.checkselfpermission(mainactivity.this, manifest.permission.camera)
!= packagemanager.permission_granted) {
return;
}
try {
manager.opencamera("0", new cameradevice.statecallback() {
@override
public void onopened(@nonnull cameradevice camera) {
try {
surfacetexture surfacetexture = textureview.getsurfacetexture();
surfacetexture.setdefaultbuffersize(1440,1080);
surface surface = new surface(surfacetexture);
builder = camera.createcapturerequest(cameradevice.template_preview);
builder.addtarget(surface);
camera.createcapturesession(arrays.aslist(surface),
new cameracapturesession.statecallback() {
@override
public void onconfigured(@nonnull cameracapturesession session) {
try {
session.setrepeatingrequest(builder.build(), null, null);
} catch (cameraaccessexception e) {
e.printstacktrace();
}
}
@override
public void onconfigurefailed(@nonnull cameracapturesession session) {
}
}, null);
} catch (cameraaccessexception e) {
e.printstacktrace();
}
}
@override
public void ondisconnected(@nonnull cameradevice camera) {
}
@override
public void onerror(@nonnull cameradevice camera, int error) {
}
}, null);
} catch (cameraaccessexception e) {
e.printstacktrace();
}
}
}这样就成功使用camera2的api打开并预览了（代码里去掉3个接口中未实现的方法）
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